1b2441318SGreg Kroah-Hartman# SPDX-License-Identifier: GPL-2.0 2daa93fabSSam Ravnborg# Select 32 or 64 bit 3daa93fabSSam Ravnborgconfig 64BIT 4104daea1SMasahiro Yamada bool "64-bit kernel" if "$(ARCH)" = "x86" 5104daea1SMasahiro Yamada default "$(ARCH)" != "i386" 6a7f7f624SMasahiro Yamada help 7daa93fabSSam Ravnborg Say yes to build a 64-bit kernel - formerly known as x86_64 8daa93fabSSam Ravnborg Say no to build a 32-bit kernel - formerly known as i386 9daa93fabSSam Ravnborg 10daa93fabSSam Ravnborgconfig X86_32 113120e25eSJan Beulich def_bool y 123120e25eSJan Beulich depends on !64BIT 13341c787eSIngo Molnar # Options that are inherently 32-bit kernel only: 14341c787eSIngo Molnar select ARCH_WANT_IPC_PARSE_VERSION 15341c787eSIngo Molnar select CLKSRC_I8253 16341c787eSIngo Molnar select CLONE_BACKWARDS 17157e118bSThomas Gleixner select GENERIC_VDSO_32 18117ed454SThomas Gleixner select HAVE_DEBUG_STACKOVERFLOW 19157e118bSThomas Gleixner select KMAP_LOCAL 20341c787eSIngo Molnar select MODULES_USE_ELF_REL 21341c787eSIngo Molnar select OLD_SIGACTION 222ca408d9SBrian Gerst select ARCH_SPLIT_ARG64 23daa93fabSSam Ravnborg 24daa93fabSSam Ravnborgconfig X86_64 253120e25eSJan Beulich def_bool y 263120e25eSJan Beulich depends on 64BIT 27d94e0685SIngo Molnar # Options that are inherently 64-bit kernel only: 284eb0716eSAlexandre Ghiti select ARCH_HAS_GIGANTIC_PAGE 29c12d3362SArd Biesheuvel select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 30d94e0685SIngo Molnar select ARCH_USE_CMPXCHG_LOCKREF 31d94e0685SIngo Molnar select HAVE_ARCH_SOFT_DIRTY 32d94e0685SIngo Molnar select MODULES_USE_ELF_RELA 33f616ab59SChristoph Hellwig select NEED_DMA_MAP_STATE 3409230cbcSChristoph Hellwig select SWIOTLB 351032c0baSSam Ravnborg 36518049d9SSteven Rostedt (VMware)config FORCE_DYNAMIC_FTRACE 37518049d9SSteven Rostedt (VMware) def_bool y 38518049d9SSteven Rostedt (VMware) depends on X86_32 39518049d9SSteven Rostedt (VMware) depends on FUNCTION_TRACER 40518049d9SSteven Rostedt (VMware) select DYNAMIC_FTRACE 41518049d9SSteven Rostedt (VMware) help 42518049d9SSteven Rostedt (VMware) We keep the static function tracing (!DYNAMIC_FTRACE) around 43518049d9SSteven Rostedt (VMware) in order to test the non static function tracing in the 44518049d9SSteven Rostedt (VMware) generic code, as other architectures still use it. But we 45518049d9SSteven Rostedt (VMware) only need to keep it around for x86_64. No need to keep it 46518049d9SSteven Rostedt (VMware) for x86_32. For x86_32, force DYNAMIC_FTRACE. 47d94e0685SIngo Molnar# 48d94e0685SIngo Molnar# Arch settings 49d94e0685SIngo Molnar# 50d94e0685SIngo Molnar# ( Note that options that are marked 'if X86_64' could in principle be 51d94e0685SIngo Molnar# ported to 32-bit as well. ) 52d94e0685SIngo Molnar# 538d5fffb9SSam Ravnborgconfig X86 543c2362e6SHarvey Harrison def_bool y 55c763ea26SIngo Molnar # 56c763ea26SIngo Molnar # Note: keep this list sorted alphabetically 57c763ea26SIngo Molnar # 586471b825SIngo Molnar select ACPI_LEGACY_TABLES_LOOKUP if ACPI 596e0a0ea1SGraeme Gregory select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 60942fa985SYury Norov select ARCH_32BIT_OFF_T if X86_32 612a21ad57SThomas Gleixner select ARCH_CLOCKSOURCE_INIT 6291dda51aSAleksey Makarov select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 63fa5b6ec9SLaura Abbott select ARCH_HAS_DEBUG_VIRTUAL 64399145f9SAnshuman Khandual select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 6521266be9SDan Williams select ARCH_HAS_DEVMEM_IS_ALLOWED 66b1a57bbfSDouglas Anderson select ARCH_HAS_EARLY_DEBUG if KGDB 676471b825SIngo Molnar select ARCH_HAS_ELF_RANDOMIZE 6872d93104SLinus Torvalds select ARCH_HAS_FAST_MULTIPLIER 69316d097cSDave Hansen select ARCH_HAS_FILTER_PGPROT 706974f0c4SDaniel Micay select ARCH_HAS_FORTIFY_SOURCE 71957e3facSRiku Voipio select ARCH_HAS_GCOV_PROFILE_ALL 720f1441b4SPeter Zijlstra select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION 730c9c1d56SThiago Jung Bauermann select ARCH_HAS_MEM_ENCRYPT 7410bcc80eSMathieu Desnoyers select ARCH_HAS_MEMBARRIER_SYNC_CORE 750ebeea8cSDaniel Borkmann select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 76c763ea26SIngo Molnar select ARCH_HAS_PMEM_API if X86_64 7717596731SRobin Murphy select ARCH_HAS_PTE_DEVMAP if X86_64 783010a5eaSLaurent Dufour select ARCH_HAS_PTE_SPECIAL 790aed55afSDan Williams select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 80ec6347bbSDan Williams select ARCH_HAS_COPY_MC if X86_64 81d2852a22SDaniel Borkmann select ARCH_HAS_SET_MEMORY 82d253ca0cSRick Edgecombe select ARCH_HAS_SET_DIRECT_MAP 83ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_KERNEL_RWX 84ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_MODULE_RWX 85ac1ab12aSMathieu Desnoyers select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 8625c619e5SBrian Gerst select ARCH_HAS_SYSCALL_WRAPPER 87c6d30853SAndrey Ryabinin select ARCH_HAS_UBSAN_SANITIZE_ALL 887e01ccb4SZong Li select ARCH_HAS_DEBUG_WX 896471b825SIngo Molnar select ARCH_HAVE_NMI_SAFE_CMPXCHG 906471b825SIngo Molnar select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 9177fbbc81SMark Salter select ARCH_MIGHT_HAVE_PC_PARPORT 925e2c18c0SMark Salter select ARCH_MIGHT_HAVE_PC_SERIO 933599fe12SThomas Gleixner select ARCH_STACKWALK 942c870e61SArnd Bergmann select ARCH_SUPPORTS_ACPI 956471b825SIngo Molnar select ARCH_SUPPORTS_ATOMIC_RMW 965d6ad668SMike Rapoport select ARCH_SUPPORTS_DEBUG_PAGEALLOC 976471b825SIngo Molnar select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 9814df3267SThomas Gleixner select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 996471b825SIngo Molnar select ARCH_USE_BUILTIN_BSWAP 1006471b825SIngo Molnar select ARCH_USE_QUEUED_RWLOCKS 1016471b825SIngo Molnar select ARCH_USE_QUEUED_SPINLOCKS 1022ce0d7f9SMark Brown select ARCH_USE_SYM_ANNOTATIONS 103ce4a4e56SAndy Lutomirski select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 10481c22041SDaniel Borkmann select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 105c763ea26SIngo Molnar select ARCH_WANTS_DYNAMIC_TASK_STRUCT 1063876d4a3SAlexandre Ghiti select ARCH_WANT_HUGE_PMD_SHARE 10759612b24SNathan Chancellor select ARCH_WANT_LD_ORPHAN_WARN 10838d8b4e6SHuang Ying select ARCH_WANTS_THP_SWAP if X86_64 10910916706SShile Zhang select BUILDTIME_TABLE_SORT 1106471b825SIngo Molnar select CLKEVT_I8253 1116471b825SIngo Molnar select CLOCKSOURCE_VALIDATE_LAST_CYCLE 1126471b825SIngo Molnar select CLOCKSOURCE_WATCHDOG 1136471b825SIngo Molnar select DCACHE_WORD_ACCESS 11445471cd9SLinus Torvalds select EDAC_ATOMIC_SCRUB 11545471cd9SLinus Torvalds select EDAC_SUPPORT 1166471b825SIngo Molnar select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 1176471b825SIngo Molnar select GENERIC_CLOCKEVENTS_MIN_ADJUST 1186471b825SIngo Molnar select GENERIC_CMOS_UPDATE 1196471b825SIngo Molnar select GENERIC_CPU_AUTOPROBE 12061dc0f55SThomas Gleixner select GENERIC_CPU_VULNERABILITIES 1216471b825SIngo Molnar select GENERIC_EARLY_IOREMAP 12227d6b4d1SThomas Gleixner select GENERIC_ENTRY 1236471b825SIngo Molnar select GENERIC_FIND_FIRST_BIT 1246471b825SIngo Molnar select GENERIC_IOMAP 125c7d6c9ddSThomas Gleixner select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 1260fa115daSThomas Gleixner select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 127ad7a929fSThomas Gleixner select GENERIC_IRQ_MIGRATION if SMP 1286471b825SIngo Molnar select GENERIC_IRQ_PROBE 129c201c917SThomas Gleixner select GENERIC_IRQ_RESERVATION_MODE 1306471b825SIngo Molnar select GENERIC_IRQ_SHOW 1316471b825SIngo Molnar select GENERIC_PENDING_IRQ if SMP 1322ae27137SSteven Price select GENERIC_PTDUMP 1336471b825SIngo Molnar select GENERIC_SMP_IDLE_THREAD 1346471b825SIngo Molnar select GENERIC_STRNCPY_FROM_USER 1356471b825SIngo Molnar select GENERIC_STRNLEN_USER 1366471b825SIngo Molnar select GENERIC_TIME_VSYSCALL 1377ac87074SVincenzo Frascino select GENERIC_GETTIMEOFDAY 138550a77a7SDmitry Safonov select GENERIC_VDSO_TIME_NS 13939656e83SChristoph Hellwig select GUP_GET_PTE_LOW_HIGH if X86_PAE 14017e5888eSHans de Goede select HARDIRQS_SW_RESEND 1417edaeb68SThomas Gleixner select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 1426471b825SIngo Molnar select HAVE_ACPI_APEI if ACPI 1436471b825SIngo Molnar select HAVE_ACPI_APEI_NMI if ACPI 1446471b825SIngo Molnar select HAVE_ALIGNED_STRUCT_PAGE if SLUB 1456471b825SIngo Molnar select HAVE_ARCH_AUDITSYSCALL 1466471b825SIngo Molnar select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 1476471b825SIngo Molnar select HAVE_ARCH_JUMP_LABEL 148b34006c4SArd Biesheuvel select HAVE_ARCH_JUMP_LABEL_RELATIVE 149d17a1d97SAndrey Ryabinin select HAVE_ARCH_KASAN if X86_64 1500609ae01SDaniel Axtens select HAVE_ARCH_KASAN_VMALLOC if X86_64 1516471b825SIngo Molnar select HAVE_ARCH_KGDB 1529e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_BITS if MMU 1539e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 1541b028f78SDmitry Safonov select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 155271ca788SArd Biesheuvel select HAVE_ARCH_PREL32_RELOCATIONS 1566471b825SIngo Molnar select HAVE_ARCH_SECCOMP_FILTER 157f7d83c1cSKees Cook select HAVE_ARCH_THREAD_STRUCT_WHITELIST 158afaef01cSAlexander Popov select HAVE_ARCH_STACKLEAK 1596471b825SIngo Molnar select HAVE_ARCH_TRACEHOOK 1606471b825SIngo Molnar select HAVE_ARCH_TRANSPARENT_HUGEPAGE 161a00cc7d9SMatthew Wilcox select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 162b64d8d1eSPeter Xu select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 163e37e43a4SAndy Lutomirski select HAVE_ARCH_VMAP_STACK if X86_64 164c763ea26SIngo Molnar select HAVE_ARCH_WITHIN_STACK_FRAMES 1652ff2b7ecSMasahiro Yamada select HAVE_ASM_MODVERSIONS 1666471b825SIngo Molnar select HAVE_CMPXCHG_DOUBLE 1676471b825SIngo Molnar select HAVE_CMPXCHG_LOCAL 1686471b825SIngo Molnar select HAVE_CONTEXT_TRACKING if X86_64 169d1f250e2SFrederic Weisbecker select HAVE_CONTEXT_TRACKING_OFFSTACK if HAVE_CONTEXT_TRACKING 1706471b825SIngo Molnar select HAVE_C_RECORDMCOUNT 1716471b825SIngo Molnar select HAVE_DEBUG_KMEMLEAK 1729c5a3621SAkinobu Mita select HAVE_DMA_CONTIGUOUS 173677aa9f7SSteven Rostedt select HAVE_DYNAMIC_FTRACE 17406aeaaeaSMasami Hiramatsu select HAVE_DYNAMIC_FTRACE_WITH_REGS 17502a474caSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 176562955feSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 17703f5781bSWang YanQing select HAVE_EBPF_JIT 17858340a07SJohannes Berg select HAVE_EFFICIENT_UNALIGNED_ACCESS 1796630a8e5SChristoph Hellwig select HAVE_EISA 1805f56a5dfSJiri Slaby select HAVE_EXIT_THREAD 18167a929e0SChristoph Hellwig select HAVE_FAST_GUP 182644e0e8dSSteven Rostedt (VMware) select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 1836471b825SIngo Molnar select HAVE_FTRACE_MCOUNT_RECORD 1846471b825SIngo Molnar select HAVE_FUNCTION_GRAPH_TRACER 1856471b825SIngo Molnar select HAVE_FUNCTION_TRACER 1866b90bd4bSEmese Revfy select HAVE_GCC_PLUGINS 1870067f129SK.Prasad select HAVE_HW_BREAKPOINT 1886471b825SIngo Molnar select HAVE_IDE 1896471b825SIngo Molnar select HAVE_IOREMAP_PROT 1906471b825SIngo Molnar select HAVE_IRQ_TIME_ACCOUNTING 1916471b825SIngo Molnar select HAVE_KERNEL_BZIP2 1926471b825SIngo Molnar select HAVE_KERNEL_GZIP 1936471b825SIngo Molnar select HAVE_KERNEL_LZ4 1946471b825SIngo Molnar select HAVE_KERNEL_LZMA 1956471b825SIngo Molnar select HAVE_KERNEL_LZO 1966471b825SIngo Molnar select HAVE_KERNEL_XZ 197fb46d057SNick Terrell select HAVE_KERNEL_ZSTD 1986471b825SIngo Molnar select HAVE_KPROBES 1996471b825SIngo Molnar select HAVE_KPROBES_ON_FTRACE 200540adea3SMasami Hiramatsu select HAVE_FUNCTION_ERROR_INJECTION 2016471b825SIngo Molnar select HAVE_KRETPROBES 2026471b825SIngo Molnar select HAVE_KVM 2036471b825SIngo Molnar select HAVE_LIVEPATCH if X86_64 2040102752eSFrederic Weisbecker select HAVE_MIXED_BREAKPOINTS_REGS 205ee9f8fceSJosh Poimboeuf select HAVE_MOD_ARCH_SPECIFIC 2069f132f7eSJoel Fernandes (Google) select HAVE_MOVE_PMD 207be37c98dSKalesh Singh select HAVE_MOVE_PUD 20842a0bb3fSPetr Mladek select HAVE_NMI 2096471b825SIngo Molnar select HAVE_OPROFILE 2106471b825SIngo Molnar select HAVE_OPTPROBES 2116471b825SIngo Molnar select HAVE_PCSPKR_PLATFORM 2126471b825SIngo Molnar select HAVE_PERF_EVENTS 213c01d4323SFrederic Weisbecker select HAVE_PERF_EVENTS_NMI 21492e5aae4SNicholas Piggin select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 215eb01d42aSChristoph Hellwig select HAVE_PCI 216c5e63197SJiri Olsa select HAVE_PERF_REGS 217c5ebcedbSJiri Olsa select HAVE_PERF_USER_STACK_DUMP 218ff2e6d72SPeter Zijlstra select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 21900998085SThomas Gleixner select HAVE_POSIX_CPU_TIMERS_TASK_WORK 2206471b825SIngo Molnar select HAVE_REGS_AND_STACK_ACCESS_API 2216415b38bSJiri Slaby select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 2223c88ee19SMasami Hiramatsu select HAVE_FUNCTION_ARG_ACCESS_API 223d148eac0SMasahiro Yamada select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 224c763ea26SIngo Molnar select HAVE_STACK_VALIDATION if X86_64 225e6d6c071SJosh Poimboeuf select HAVE_STATIC_CALL 2261e7e4788SJosh Poimboeuf select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION 227d6761b8fSMathieu Desnoyers select HAVE_RSEQ 2286471b825SIngo Molnar select HAVE_SYSCALL_TRACEPOINTS 2296471b825SIngo Molnar select HAVE_UNSTABLE_SCHED_CLOCK 2307c68af6eSAvi Kivity select HAVE_USER_RETURN_NOTIFIER 2317ac87074SVincenzo Frascino select HAVE_GENERIC_VDSO 23205736e4aSThomas Gleixner select HOTPLUG_SMT if SMP 233c0185808SThomas Gleixner select IRQ_FORCED_THREADING 23486596f0aSChristoph Hellwig select NEED_SG_DMA_LENGTH 2352eac9c2dSChristoph Hellwig select PCI_DOMAINS if PCI 236625210cfSSinan Kaya select PCI_LOCKLESS_CONFIG if PCI 2376471b825SIngo Molnar select PERF_EVENTS 2383195ef59SPrarit Bhargava select RTC_LIB 239d6faca40SArnd Bergmann select RTC_MC146818_LIB 2406471b825SIngo Molnar select SPARSE_IRQ 24183fe27eaSPranith Kumar select SRCU 2421e7e4788SJosh Poimboeuf select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE) 2436471b825SIngo Molnar select SYSCTL_EXCEPTION_TRACE 24415f4eae7SAndy Lutomirski select THREAD_INFO_IN_TASK 2456471b825SIngo Molnar select USER_STACKTRACE_SUPPORT 2466471b825SIngo Molnar select VIRT_TO_BUS 2473b02a051SIngo Molnar select HAVE_ARCH_KCSAN if X86_64 2486471b825SIngo Molnar select X86_FEATURE_NAMES if PROC_FS 2490c608dadSAubrey Li select PROC_PID_ARCH_STATUS if PROC_FS 2509e2b4be3SNayna Jain imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 2517d8330a5SBalbir Singh 252ba7e4d13SIngo Molnarconfig INSTRUCTION_DECODER 2533120e25eSJan Beulich def_bool y 2543120e25eSJan Beulich depends on KPROBES || PERF_EVENTS || UPROBES 255ba7e4d13SIngo Molnar 25651b26adaSLinus Torvaldsconfig OUTPUT_FORMAT 25751b26adaSLinus Torvalds string 25851b26adaSLinus Torvalds default "elf32-i386" if X86_32 25951b26adaSLinus Torvalds default "elf64-x86-64" if X86_64 26051b26adaSLinus Torvalds 2618d5fffb9SSam Ravnborgconfig LOCKDEP_SUPPORT 2623c2362e6SHarvey Harrison def_bool y 2638d5fffb9SSam Ravnborg 2648d5fffb9SSam Ravnborgconfig STACKTRACE_SUPPORT 2653c2362e6SHarvey Harrison def_bool y 2668d5fffb9SSam Ravnborg 2678d5fffb9SSam Ravnborgconfig MMU 2683c2362e6SHarvey Harrison def_bool y 2698d5fffb9SSam Ravnborg 2709e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN 2719e08f57dSDaniel Cashman default 28 if 64BIT 2729e08f57dSDaniel Cashman default 8 2739e08f57dSDaniel Cashman 2749e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX 2759e08f57dSDaniel Cashman default 32 if 64BIT 2769e08f57dSDaniel Cashman default 16 2779e08f57dSDaniel Cashman 2789e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN 2799e08f57dSDaniel Cashman default 8 2809e08f57dSDaniel Cashman 2819e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX 2829e08f57dSDaniel Cashman default 16 2839e08f57dSDaniel Cashman 2848d5fffb9SSam Ravnborgconfig SBUS 2858d5fffb9SSam Ravnborg bool 2868d5fffb9SSam Ravnborg 2878d5fffb9SSam Ravnborgconfig GENERIC_ISA_DMA 2883120e25eSJan Beulich def_bool y 2893120e25eSJan Beulich depends on ISA_DMA_API 2908d5fffb9SSam Ravnborg 2918d5fffb9SSam Ravnborgconfig GENERIC_BUG 2923c2362e6SHarvey Harrison def_bool y 2938d5fffb9SSam Ravnborg depends on BUG 294b93a531eSJan Beulich select GENERIC_BUG_RELATIVE_POINTERS if X86_64 295b93a531eSJan Beulich 296b93a531eSJan Beulichconfig GENERIC_BUG_RELATIVE_POINTERS 297b93a531eSJan Beulich bool 2988d5fffb9SSam Ravnborg 2998d5fffb9SSam Ravnborgconfig ARCH_MAY_HAVE_PC_FDC 3003120e25eSJan Beulich def_bool y 3013120e25eSJan Beulich depends on ISA_DMA_API 3028d5fffb9SSam Ravnborg 3031032c0baSSam Ravnborgconfig GENERIC_CALIBRATE_DELAY 3041032c0baSSam Ravnborg def_bool y 3051032c0baSSam Ravnborg 3069a0b8415Svenkatesh.pallipadi@intel.comconfig ARCH_HAS_CPU_RELAX 3079a0b8415Svenkatesh.pallipadi@intel.com def_bool y 3088d5fffb9SSam Ravnborg 3091b27d05bSPekka Enbergconfig ARCH_HAS_CACHE_LINE_SIZE 3101b27d05bSPekka Enberg def_bool y 3111b27d05bSPekka Enberg 312316d097cSDave Hansenconfig ARCH_HAS_FILTER_PGPROT 313316d097cSDave Hansen def_bool y 314316d097cSDave Hansen 315dd5af90aSMike Travisconfig HAVE_SETUP_PER_CPU_AREA 31689c9c4c5SBrian Gerst def_bool y 317b32ef636Stravis@sgi.com 31808fc4580STejun Heoconfig NEED_PER_CPU_EMBED_FIRST_CHUNK 31908fc4580STejun Heo def_bool y 32008fc4580STejun Heo 32108fc4580STejun Heoconfig NEED_PER_CPU_PAGE_FIRST_CHUNK 32211124411STejun Heo def_bool y 32311124411STejun Heo 324801e4062SJohannes Bergconfig ARCH_HIBERNATION_POSSIBLE 325801e4062SJohannes Berg def_bool y 326801e4062SJohannes Berg 327f4cb5700SJohannes Bergconfig ARCH_SUSPEND_POSSIBLE 328f4cb5700SJohannes Berg def_bool y 329f4cb5700SJohannes Berg 33053313b2cSSteve Capperconfig ARCH_WANT_GENERAL_HUGETLB 33153313b2cSSteve Capper def_bool y 33253313b2cSSteve Capper 3338d5fffb9SSam Ravnborgconfig ZONE_DMA32 334e0fd24a3SJan Beulich def_bool y if X86_64 3358d5fffb9SSam Ravnborg 3368d5fffb9SSam Ravnborgconfig AUDIT_ARCH 337e0fd24a3SJan Beulich def_bool y if X86_64 3388d5fffb9SSam Ravnborg 339d6f2d75aSAndrey Ryabininconfig KASAN_SHADOW_OFFSET 340d6f2d75aSAndrey Ryabinin hex 341d6f2d75aSAndrey Ryabinin depends on KASAN 342d6f2d75aSAndrey Ryabinin default 0xdffffc0000000000 343d6f2d75aSAndrey Ryabinin 34469575d38SShane Wangconfig HAVE_INTEL_TXT 34569575d38SShane Wang def_bool y 3466ea30386SKees Cook depends on INTEL_IOMMU && ACPI 34769575d38SShane Wang 3486b0c3d44SSam Ravnborgconfig X86_32_SMP 3496b0c3d44SSam Ravnborg def_bool y 3506b0c3d44SSam Ravnborg depends on X86_32 && SMP 3516b0c3d44SSam Ravnborg 3526b0c3d44SSam Ravnborgconfig X86_64_SMP 3536b0c3d44SSam Ravnborg def_bool y 3546b0c3d44SSam Ravnborg depends on X86_64 && SMP 3556b0c3d44SSam Ravnborg 356ccbeed3aSTejun Heoconfig X86_32_LAZY_GS 357ccbeed3aSTejun Heo def_bool y 3588458f8c2SMasahiro Yamada depends on X86_32 && !STACKPROTECTOR 359ccbeed3aSTejun Heo 3602b144498SSrikar Dronamrajuconfig ARCH_SUPPORTS_UPROBES 3612b144498SSrikar Dronamraju def_bool y 3622b144498SSrikar Dronamraju 363d20642f0SRob Herringconfig FIX_EARLYCON_MEM 364d20642f0SRob Herring def_bool y 365d20642f0SRob Herring 36694d49eb3SKirill A. Shutemovconfig DYNAMIC_PHYSICAL_MASK 36794d49eb3SKirill A. Shutemov bool 36894d49eb3SKirill A. Shutemov 36998233368SKirill A. Shutemovconfig PGTABLE_LEVELS 37098233368SKirill A. Shutemov int 37177ef56e4SKirill A. Shutemov default 5 if X86_5LEVEL 37298233368SKirill A. Shutemov default 4 if X86_64 37398233368SKirill A. Shutemov default 3 if X86_PAE 37498233368SKirill A. Shutemov default 2 37598233368SKirill A. Shutemov 3762a61f474SMasahiro Yamadaconfig CC_HAS_SANE_STACKPROTECTOR 3772a61f474SMasahiro Yamada bool 3782a61f474SMasahiro Yamada default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 3792a61f474SMasahiro Yamada default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 3802a61f474SMasahiro Yamada help 3812a61f474SMasahiro Yamada We have to make sure stack protector is unconditionally disabled if 3822a61f474SMasahiro Yamada the compiler produces broken code. 3832a61f474SMasahiro Yamada 384506f1d07SSam Ravnborgmenu "Processor type and features" 385506f1d07SSam Ravnborg 3865ee71535SRandy Dunlapconfig ZONE_DMA 3875ee71535SRandy Dunlap bool "DMA memory allocation support" if EXPERT 3885ee71535SRandy Dunlap default y 3895ee71535SRandy Dunlap help 3905ee71535SRandy Dunlap DMA memory allocation support allows devices with less than 32-bit 3915ee71535SRandy Dunlap addressing to allocate within the first 16MB of address space. 3925ee71535SRandy Dunlap Disable if no such devices will be used. 3935ee71535SRandy Dunlap 3945ee71535SRandy Dunlap If unsure, say Y. 3955ee71535SRandy Dunlap 396506f1d07SSam Ravnborgconfig SMP 397506f1d07SSam Ravnborg bool "Symmetric multi-processing support" 398a7f7f624SMasahiro Yamada help 399506f1d07SSam Ravnborg This enables support for systems with more than one CPU. If you have 4004a474157SRobert Graffham a system with only one CPU, say N. If you have a system with more 4014a474157SRobert Graffham than one CPU, say Y. 402506f1d07SSam Ravnborg 4034a474157SRobert Graffham If you say N here, the kernel will run on uni- and multiprocessor 404506f1d07SSam Ravnborg machines, but will use only one CPU of a multiprocessor machine. If 405506f1d07SSam Ravnborg you say Y here, the kernel will run on many, but not all, 4064a474157SRobert Graffham uniprocessor machines. On a uniprocessor machine, the kernel 407506f1d07SSam Ravnborg will run faster if you say N here. 408506f1d07SSam Ravnborg 409506f1d07SSam Ravnborg Note that if you say Y here and choose architecture "586" or 410506f1d07SSam Ravnborg "Pentium" under "Processor family", the kernel will not work on 486 411506f1d07SSam Ravnborg architectures. Similarly, multiprocessor kernels for the "PPro" 412506f1d07SSam Ravnborg architecture may not work on all Pentium based boards. 413506f1d07SSam Ravnborg 414506f1d07SSam Ravnborg People using multiprocessor machines who say Y here should also say 415506f1d07SSam Ravnborg Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 416506f1d07SSam Ravnborg Management" code will be disabled if you say Y here. 417506f1d07SSam Ravnborg 418cb1aaebeSMauro Carvalho Chehab See also <file:Documentation/x86/i386/IO-APIC.rst>, 4194f4cfa6cSMauro Carvalho Chehab <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 420506f1d07SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 421506f1d07SSam Ravnborg 422506f1d07SSam Ravnborg If you don't know what to do here, say N. 423506f1d07SSam Ravnborg 4249def39beSJosh Triplettconfig X86_FEATURE_NAMES 4259def39beSJosh Triplett bool "Processor feature human-readable names" if EMBEDDED 4269def39beSJosh Triplett default y 427a7f7f624SMasahiro Yamada help 4289def39beSJosh Triplett This option compiles in a table of x86 feature bits and corresponding 4299def39beSJosh Triplett names. This is required to support /proc/cpuinfo and a few kernel 4309def39beSJosh Triplett messages. You can disable this to save space, at the expense of 4319def39beSJosh Triplett making those few kernel messages show numeric feature bits instead. 4329def39beSJosh Triplett 4339def39beSJosh Triplett If in doubt, say Y. 4349def39beSJosh Triplett 43506cd9a7dSYinghai Luconfig X86_X2APIC 43606cd9a7dSYinghai Lu bool "Support x2apic" 43719e3d60dSJan Kiszka depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 438a7f7f624SMasahiro Yamada help 43906cd9a7dSYinghai Lu This enables x2apic support on CPUs that have this feature. 44006cd9a7dSYinghai Lu 44106cd9a7dSYinghai Lu This allows 32-bit apic IDs (so it can support very large systems), 44206cd9a7dSYinghai Lu and accesses the local apic via MSRs not via mmio. 44306cd9a7dSYinghai Lu 44406cd9a7dSYinghai Lu If you don't know what to do here, say N. 44506cd9a7dSYinghai Lu 4466695c85bSYinghai Luconfig X86_MPPARSE 447*4590d98fSAndy Shevchenko bool "Enable MPS table" if ACPI 4487a527688SJan Beulich default y 4495ab74722SIngo Molnar depends on X86_LOCAL_APIC 450a7f7f624SMasahiro Yamada help 4516695c85bSYinghai Lu For old smp systems that do not have proper acpi support. Newer systems 4526695c85bSYinghai Lu (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 4536695c85bSYinghai Lu 454ddd70cf9SJun Nakajimaconfig GOLDFISH 455ddd70cf9SJun Nakajima def_bool y 456ddd70cf9SJun Nakajima depends on X86_GOLDFISH 457ddd70cf9SJun Nakajima 45876b04384SDavid Woodhouseconfig RETPOLINE 45976b04384SDavid Woodhouse bool "Avoid speculative indirect branches in kernel" 46076b04384SDavid Woodhouse default y 46176b04384SDavid Woodhouse help 46276b04384SDavid Woodhouse Compile kernel with the retpoline compiler options to guard against 46376b04384SDavid Woodhouse kernel-to-user data leaks by avoiding speculative indirect 46476b04384SDavid Woodhouse branches. Requires a compiler with -mindirect-branch=thunk-extern 46576b04384SDavid Woodhouse support for full protection. The kernel may run slower. 46676b04384SDavid Woodhouse 467e6d42931SJohannes Weinerconfig X86_CPU_RESCTRL 468e6d42931SJohannes Weiner bool "x86 CPU resource control support" 4696fe07ce3SBabu Moger depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 47059fe5a77SThomas Gleixner select KERNFS 471e79f15a4SChen Yu select PROC_CPU_RESCTRL if PROC_FS 47278e99b4aSFenghua Yu help 473e6d42931SJohannes Weiner Enable x86 CPU resource control support. 4746fe07ce3SBabu Moger 4756fe07ce3SBabu Moger Provide support for the allocation and monitoring of system resources 4766fe07ce3SBabu Moger usage by the CPU. 4776fe07ce3SBabu Moger 4786fe07ce3SBabu Moger Intel calls this Intel Resource Director Technology 4796fe07ce3SBabu Moger (Intel(R) RDT). More information about RDT can be found in the 4806fe07ce3SBabu Moger Intel x86 Architecture Software Developer Manual. 4816fe07ce3SBabu Moger 4826fe07ce3SBabu Moger AMD calls this AMD Platform Quality of Service (AMD QoS). 4836fe07ce3SBabu Moger More information about AMD QoS can be found in the AMD64 Technology 4846fe07ce3SBabu Moger Platform Quality of Service Extensions manual. 48578e99b4aSFenghua Yu 48678e99b4aSFenghua Yu Say N if unsure. 48778e99b4aSFenghua Yu 4888425091fSRavikiran G Thirumalaiif X86_32 489a0d0bb4dSRandy Dunlapconfig X86_BIGSMP 490a0d0bb4dSRandy Dunlap bool "Support for big SMP systems with more than 8 CPUs" 491a0d0bb4dSRandy Dunlap depends on SMP 492a7f7f624SMasahiro Yamada help 493e133f6eaSRandy Dunlap This option is needed for the systems that have more than 8 CPUs. 494a0d0bb4dSRandy Dunlap 495c5c606d9SRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 496c5c606d9SRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 497c5c606d9SRavikiran G Thirumalai default y 498a7f7f624SMasahiro Yamada help 49906ac8346SIngo Molnar If you disable this option then the kernel will only support 50006ac8346SIngo Molnar standard PC platforms. (which covers the vast majority of 50106ac8346SIngo Molnar systems out there.) 50206ac8346SIngo Molnar 5038425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5048425091fSRavikiran G Thirumalai for the following (non-PC) 32 bit x86 platforms: 505cb7b8023SBen Hutchings Goldfish (Android emulator) 5068425091fSRavikiran G Thirumalai AMD Elan 5078425091fSRavikiran G Thirumalai RDC R-321x SoC 5088425091fSRavikiran G Thirumalai SGI 320/540 (Visual Workstation) 50983125a3aSAlessandro Rubini STA2X11-based (e.g. Northville) 5103f4110a4SThomas Gleixner Moorestown MID devices 51106ac8346SIngo Molnar 51206ac8346SIngo Molnar If you have one of these systems, or if you want to build a 51306ac8346SIngo Molnar generic distribution kernel, say Y here - otherwise say N. 5148425091fSRavikiran G Thirumalaiendif 51506ac8346SIngo Molnar 5168425091fSRavikiran G Thirumalaiif X86_64 5178425091fSRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 5188425091fSRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 5198425091fSRavikiran G Thirumalai default y 520a7f7f624SMasahiro Yamada help 5218425091fSRavikiran G Thirumalai If you disable this option then the kernel will only support 5228425091fSRavikiran G Thirumalai standard PC platforms. (which covers the vast majority of 5238425091fSRavikiran G Thirumalai systems out there.) 5248425091fSRavikiran G Thirumalai 5258425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5268425091fSRavikiran G Thirumalai for the following (non-PC) 64 bit x86 platforms: 52744b111b5SSteffen Persvold Numascale NumaChip 5288425091fSRavikiran G Thirumalai ScaleMP vSMP 5298425091fSRavikiran G Thirumalai SGI Ultraviolet 5308425091fSRavikiran G Thirumalai 5318425091fSRavikiran G Thirumalai If you have one of these systems, or if you want to build a 5328425091fSRavikiran G Thirumalai generic distribution kernel, say Y here - otherwise say N. 5338425091fSRavikiran G Thirumalaiendif 534c5c606d9SRavikiran G Thirumalai# This is an alphabetically sorted list of 64 bit extended platforms 535c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 53644b111b5SSteffen Persvoldconfig X86_NUMACHIP 53744b111b5SSteffen Persvold bool "Numascale NumaChip" 53844b111b5SSteffen Persvold depends on X86_64 53944b111b5SSteffen Persvold depends on X86_EXTENDED_PLATFORM 54044b111b5SSteffen Persvold depends on NUMA 54144b111b5SSteffen Persvold depends on SMP 54244b111b5SSteffen Persvold depends on X86_X2APIC 543f9726bfdSDaniel J Blueman depends on PCI_MMCONFIG 544a7f7f624SMasahiro Yamada help 54544b111b5SSteffen Persvold Adds support for Numascale NumaChip large-SMP systems. Needed to 54644b111b5SSteffen Persvold enable more than ~168 cores. 54744b111b5SSteffen Persvold If you don't have one of these, you should say N here. 54803b48632SNick Piggin 5496a48565eSIngo Molnarconfig X86_VSMP 550c5c606d9SRavikiran G Thirumalai bool "ScaleMP vSMP" 5516276a074SBorislav Petkov select HYPERVISOR_GUEST 5526a48565eSIngo Molnar select PARAVIRT 5536a48565eSIngo Molnar depends on X86_64 && PCI 554c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 555ead91d4bSShai Fultheim depends on SMP 556a7f7f624SMasahiro Yamada help 5576a48565eSIngo Molnar Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 5586a48565eSIngo Molnar supposed to run on these EM64T-based machines. Only choose this option 5596a48565eSIngo Molnar if you have one of these machines. 5606a48565eSIngo Molnar 561c5c606d9SRavikiran G Thirumalaiconfig X86_UV 562c5c606d9SRavikiran G Thirumalai bool "SGI Ultraviolet" 563c5c606d9SRavikiran G Thirumalai depends on X86_64 564c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 56554c28d29SJack Steiner depends on NUMA 5661ecb4ae5SAndrew Morton depends on EFI 5679d6c26e7SSuresh Siddha depends on X86_X2APIC 5681222e564SIngo Molnar depends on PCI 569a7f7f624SMasahiro Yamada help 570c5c606d9SRavikiran G Thirumalai This option is needed in order to support SGI Ultraviolet systems. 571c5c606d9SRavikiran G Thirumalai If you don't have one of these, you should say N here. 572c5c606d9SRavikiran G Thirumalai 573c5c606d9SRavikiran G Thirumalai# Following is an alphabetically sorted list of 32 bit extended platforms 574c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 575506f1d07SSam Ravnborg 576ddd70cf9SJun Nakajimaconfig X86_GOLDFISH 577ddd70cf9SJun Nakajima bool "Goldfish (Virtual Platform)" 578cb7b8023SBen Hutchings depends on X86_EXTENDED_PLATFORM 579a7f7f624SMasahiro Yamada help 580ddd70cf9SJun Nakajima Enable support for the Goldfish virtual platform used primarily 581ddd70cf9SJun Nakajima for Android development. Unless you are building for the Android 582ddd70cf9SJun Nakajima Goldfish emulator say N here. 583ddd70cf9SJun Nakajima 584c751e17bSThomas Gleixnerconfig X86_INTEL_CE 585c751e17bSThomas Gleixner bool "CE4100 TV platform" 586c751e17bSThomas Gleixner depends on PCI 587c751e17bSThomas Gleixner depends on PCI_GODIRECT 5886084a6e2SJiang Liu depends on X86_IO_APIC 589c751e17bSThomas Gleixner depends on X86_32 590c751e17bSThomas Gleixner depends on X86_EXTENDED_PLATFORM 59137bc9f50SDirk Brandewie select X86_REBOOTFIXUPS 592da6b737bSSebastian Andrzej Siewior select OF 593da6b737bSSebastian Andrzej Siewior select OF_EARLY_FLATTREE 594a7f7f624SMasahiro Yamada help 595c751e17bSThomas Gleixner Select for the Intel CE media processor (CE4100) SOC. 596c751e17bSThomas Gleixner This option compiles in support for the CE4100 SOC for settop 597c751e17bSThomas Gleixner boxes and media devices. 598c751e17bSThomas Gleixner 5994cb9b00fSDavid Cohenconfig X86_INTEL_MID 60043605ef1SAlan Cox bool "Intel MID platform support" 60143605ef1SAlan Cox depends on X86_EXTENDED_PLATFORM 602edc6bc78SDavid Cohen depends on X86_PLATFORM_DEVICES 6031ea7c673SAlan Cox depends on PCI 6043fda5bb4SAndy Shevchenko depends on X86_64 || (PCI_GOANY && X86_32) 6051ea7c673SAlan Cox depends on X86_IO_APIC 6064cb9b00fSDavid Cohen select I2C 6077c9c3a1eSAlan Cox select DW_APB_TIMER 6081ea7c673SAlan Cox select APB_TIMER 60954b34aa0SMika Westerberg select INTEL_SCU_PCI 61015a713dfSMika Westerberg select MFD_INTEL_MSIC 611a7f7f624SMasahiro Yamada help 6124cb9b00fSDavid Cohen Select to build a kernel capable of supporting Intel MID (Mobile 6134cb9b00fSDavid Cohen Internet Device) platform systems which do not have the PCI legacy 6144cb9b00fSDavid Cohen interfaces. If you are building for a PC class system say N here. 6151ea7c673SAlan Cox 6164cb9b00fSDavid Cohen Intel MID platforms are based on an Intel processor and chipset which 6174cb9b00fSDavid Cohen consume less power than most of the x86 derivatives. 61843605ef1SAlan Cox 6198bbc2a13SBryan O'Donoghueconfig X86_INTEL_QUARK 6208bbc2a13SBryan O'Donoghue bool "Intel Quark platform support" 6218bbc2a13SBryan O'Donoghue depends on X86_32 6228bbc2a13SBryan O'Donoghue depends on X86_EXTENDED_PLATFORM 6238bbc2a13SBryan O'Donoghue depends on X86_PLATFORM_DEVICES 6248bbc2a13SBryan O'Donoghue depends on X86_TSC 6258bbc2a13SBryan O'Donoghue depends on PCI 6268bbc2a13SBryan O'Donoghue depends on PCI_GOANY 6278bbc2a13SBryan O'Donoghue depends on X86_IO_APIC 6288bbc2a13SBryan O'Donoghue select IOSF_MBI 6298bbc2a13SBryan O'Donoghue select INTEL_IMR 6309ab6eb51SAndy Shevchenko select COMMON_CLK 631a7f7f624SMasahiro Yamada help 6328bbc2a13SBryan O'Donoghue Select to include support for Quark X1000 SoC. 6338bbc2a13SBryan O'Donoghue Say Y here if you have a Quark based system such as the Arduino 6348bbc2a13SBryan O'Donoghue compatible Intel Galileo. 6358bbc2a13SBryan O'Donoghue 6363d48aab1SMika Westerbergconfig X86_INTEL_LPSS 6373d48aab1SMika Westerberg bool "Intel Low Power Subsystem Support" 6385962dd22SSinan Kaya depends on X86 && ACPI && PCI 6393d48aab1SMika Westerberg select COMMON_CLK 6400f531431SMathias Nyman select PINCTRL 641eebb3e8dSAndy Shevchenko select IOSF_MBI 642a7f7f624SMasahiro Yamada help 6433d48aab1SMika Westerberg Select to build support for Intel Low Power Subsystem such as 6443d48aab1SMika Westerberg found on Intel Lynxpoint PCH. Selecting this option enables 6450f531431SMathias Nyman things like clock tree (common clock framework) and pincontrol 6460f531431SMathias Nyman which are needed by the LPSS peripheral drivers. 6473d48aab1SMika Westerberg 64892082a88SKen Xueconfig X86_AMD_PLATFORM_DEVICE 64992082a88SKen Xue bool "AMD ACPI2Platform devices support" 65092082a88SKen Xue depends on ACPI 65192082a88SKen Xue select COMMON_CLK 65292082a88SKen Xue select PINCTRL 653a7f7f624SMasahiro Yamada help 65492082a88SKen Xue Select to interpret AMD specific ACPI device to platform device 65592082a88SKen Xue such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 65692082a88SKen Xue I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 65792082a88SKen Xue implemented under PINCTRL subsystem. 65892082a88SKen Xue 659ced3ce76SDavid E. Boxconfig IOSF_MBI 660ced3ce76SDavid E. Box tristate "Intel SoC IOSF Sideband support for SoC platforms" 661ced3ce76SDavid E. Box depends on PCI 662a7f7f624SMasahiro Yamada help 663ced3ce76SDavid E. Box This option enables sideband register access support for Intel SoC 664ced3ce76SDavid E. Box platforms. On these platforms the IOSF sideband is used in lieu of 665ced3ce76SDavid E. Box MSR's for some register accesses, mostly but not limited to thermal 666ced3ce76SDavid E. Box and power. Drivers may query the availability of this device to 667ced3ce76SDavid E. Box determine if they need the sideband in order to work on these 668ced3ce76SDavid E. Box platforms. The sideband is available on the following SoC products. 669ced3ce76SDavid E. Box This list is not meant to be exclusive. 670ced3ce76SDavid E. Box - BayTrail 671ced3ce76SDavid E. Box - Braswell 672ced3ce76SDavid E. Box - Quark 673ced3ce76SDavid E. Box 674ced3ce76SDavid E. Box You should say Y if you are running a kernel on one of these SoC's. 675ced3ce76SDavid E. Box 676ed2226bdSDavid E. Boxconfig IOSF_MBI_DEBUG 677ed2226bdSDavid E. Box bool "Enable IOSF sideband access through debugfs" 678ed2226bdSDavid E. Box depends on IOSF_MBI && DEBUG_FS 679a7f7f624SMasahiro Yamada help 680ed2226bdSDavid E. Box Select this option to expose the IOSF sideband access registers (MCR, 681ed2226bdSDavid E. Box MDR, MCRX) through debugfs to write and read register information from 682ed2226bdSDavid E. Box different units on the SoC. This is most useful for obtaining device 683ed2226bdSDavid E. Box state information for debug and analysis. As this is a general access 684ed2226bdSDavid E. Box mechanism, users of this option would have specific knowledge of the 685ed2226bdSDavid E. Box device they want to access. 686ed2226bdSDavid E. Box 687ed2226bdSDavid E. Box If you don't require the option or are in doubt, say N. 688ed2226bdSDavid E. Box 689c5c606d9SRavikiran G Thirumalaiconfig X86_RDC321X 690c5c606d9SRavikiran G Thirumalai bool "RDC R-321x SoC" 691506f1d07SSam Ravnborg depends on X86_32 692c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 693c5c606d9SRavikiran G Thirumalai select M486 694c5c606d9SRavikiran G Thirumalai select X86_REBOOTFIXUPS 695a7f7f624SMasahiro Yamada help 696c5c606d9SRavikiran G Thirumalai This option is needed for RDC R-321x system-on-chip, also known 697c5c606d9SRavikiran G Thirumalai as R-8610-(G). 698c5c606d9SRavikiran G Thirumalai If you don't have one of these chips, you should say N here. 699c5c606d9SRavikiran G Thirumalai 700e0c7ae37SIngo Molnarconfig X86_32_NON_STANDARD 7019c398017SIngo Molnar bool "Support non-standard 32-bit SMP architectures" 7029c398017SIngo Molnar depends on X86_32 && SMP 703c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 704a7f7f624SMasahiro Yamada help 705b5660ba7SH. Peter Anvin This option compiles in the bigsmp and STA2X11 default 706b5660ba7SH. Peter Anvin subarchitectures. It is intended for a generic binary 707b5660ba7SH. Peter Anvin kernel. If you select them all, kernel will probe it one by 708b5660ba7SH. Peter Anvin one and will fallback to default. 709d49c4288SYinghai Lu 710c5c606d9SRavikiran G Thirumalai# Alphabetically sorted list of Non standard 32 bit platforms 711d49c4288SYinghai Lu 712d949f36fSLinus Torvaldsconfig X86_SUPPORTS_MEMORY_FAILURE 7136fc108a0SJan Beulich def_bool y 714d949f36fSLinus Torvalds # MCE code calls memory_failure(): 715d949f36fSLinus Torvalds depends on X86_MCE 716d949f36fSLinus Torvalds # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 717d949f36fSLinus Torvalds # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 718d949f36fSLinus Torvalds depends on X86_64 || !SPARSEMEM 719d949f36fSLinus Torvalds select ARCH_SUPPORTS_MEMORY_FAILURE 720d949f36fSLinus Torvalds 72183125a3aSAlessandro Rubiniconfig STA2X11 72283125a3aSAlessandro Rubini bool "STA2X11 Companion Chip Support" 72383125a3aSAlessandro Rubini depends on X86_32_NON_STANDARD && PCI 72483125a3aSAlessandro Rubini select SWIOTLB 72583125a3aSAlessandro Rubini select MFD_STA2X11 7260145071bSLinus Walleij select GPIOLIB 727a7f7f624SMasahiro Yamada help 72883125a3aSAlessandro Rubini This adds support for boards based on the STA2X11 IO-Hub, 72983125a3aSAlessandro Rubini a.k.a. "ConneXt". The chip is used in place of the standard 73083125a3aSAlessandro Rubini PC chipset, so all "standard" peripherals are missing. If this 73183125a3aSAlessandro Rubini option is selected the kernel will still be able to boot on 73283125a3aSAlessandro Rubini standard PC machines. 73383125a3aSAlessandro Rubini 73482148d1dSShérabconfig X86_32_IRIS 73582148d1dSShérab tristate "Eurobraille/Iris poweroff module" 73682148d1dSShérab depends on X86_32 737a7f7f624SMasahiro Yamada help 73882148d1dSShérab The Iris machines from EuroBraille do not have APM or ACPI support 73982148d1dSShérab to shut themselves down properly. A special I/O sequence is 74082148d1dSShérab needed to do so, which is what this module does at 74182148d1dSShérab kernel shutdown. 74282148d1dSShérab 74382148d1dSShérab This is only for Iris machines from EuroBraille. 74482148d1dSShérab 74582148d1dSShérab If unused, say N. 74682148d1dSShérab 747ae1e9130SIngo Molnarconfig SCHED_OMIT_FRAME_POINTER 7483c2362e6SHarvey Harrison def_bool y 7493c2362e6SHarvey Harrison prompt "Single-depth WCHAN output" 750a87d0914SKen Chen depends on X86 751a7f7f624SMasahiro Yamada help 752506f1d07SSam Ravnborg Calculate simpler /proc/<PID>/wchan values. If this option 753506f1d07SSam Ravnborg is disabled then wchan values will recurse back to the 754506f1d07SSam Ravnborg caller function. This provides more accurate wchan values, 755506f1d07SSam Ravnborg at the expense of slightly more scheduling overhead. 756506f1d07SSam Ravnborg 757506f1d07SSam Ravnborg If in doubt, say "Y". 758506f1d07SSam Ravnborg 7596276a074SBorislav Petkovmenuconfig HYPERVISOR_GUEST 7606276a074SBorislav Petkov bool "Linux guest support" 761a7f7f624SMasahiro Yamada help 7626276a074SBorislav Petkov Say Y here to enable options for running Linux under various hyper- 7636276a074SBorislav Petkov visors. This option enables basic hypervisor detection and platform 7646276a074SBorislav Petkov setup. 765506f1d07SSam Ravnborg 7666276a074SBorislav Petkov If you say N, all options in this submenu will be skipped and 7676276a074SBorislav Petkov disabled, and Linux guest support won't be built in. 768506f1d07SSam Ravnborg 7696276a074SBorislav Petkovif HYPERVISOR_GUEST 770506f1d07SSam Ravnborg 771e61bd94aSEduardo Pereira Habkostconfig PARAVIRT 772e61bd94aSEduardo Pereira Habkost bool "Enable paravirtualization code" 773a7f7f624SMasahiro Yamada help 774e61bd94aSEduardo Pereira Habkost This changes the kernel so it can modify itself when it is run 775e61bd94aSEduardo Pereira Habkost under a hypervisor, potentially improving performance significantly 776e61bd94aSEduardo Pereira Habkost over full virtualization. However, when run without a hypervisor 777e61bd94aSEduardo Pereira Habkost the kernel is theoretically slower and slightly larger. 778e61bd94aSEduardo Pereira Habkost 779c00a280aSJuergen Grossconfig PARAVIRT_XXL 780c00a280aSJuergen Gross bool 781c00a280aSJuergen Gross 7826276a074SBorislav Petkovconfig PARAVIRT_DEBUG 7836276a074SBorislav Petkov bool "paravirt-ops debugging" 7846276a074SBorislav Petkov depends on PARAVIRT && DEBUG_KERNEL 785a7f7f624SMasahiro Yamada help 7866276a074SBorislav Petkov Enable to debug paravirt_ops internals. Specifically, BUG if 7876276a074SBorislav Petkov a paravirt_op is missing when it is called. 7886276a074SBorislav Petkov 789b4ecc126SJeremy Fitzhardingeconfig PARAVIRT_SPINLOCKS 790b4ecc126SJeremy Fitzhardinge bool "Paravirtualization layer for spinlocks" 7916ea30386SKees Cook depends on PARAVIRT && SMP 792a7f7f624SMasahiro Yamada help 793b4ecc126SJeremy Fitzhardinge Paravirtualized spinlocks allow a pvops backend to replace the 794b4ecc126SJeremy Fitzhardinge spinlock implementation with something virtualization-friendly 795b4ecc126SJeremy Fitzhardinge (for example, block the virtual CPU rather than spinning). 796b4ecc126SJeremy Fitzhardinge 7974c4e4f61SRaghavendra K T It has a minimal impact on native kernels and gives a nice performance 7984c4e4f61SRaghavendra K T benefit on paravirtualized KVM / Xen kernels. 799b4ecc126SJeremy Fitzhardinge 8004c4e4f61SRaghavendra K T If you are unsure how to answer this question, answer Y. 801b4ecc126SJeremy Fitzhardinge 802ecca2502SZhao Yakuiconfig X86_HV_CALLBACK_VECTOR 803ecca2502SZhao Yakui def_bool n 804ecca2502SZhao Yakui 8056276a074SBorislav Petkovsource "arch/x86/xen/Kconfig" 8066276a074SBorislav Petkov 8076276a074SBorislav Petkovconfig KVM_GUEST 8086276a074SBorislav Petkov bool "KVM Guest support (including kvmclock)" 8096276a074SBorislav Petkov depends on PARAVIRT 8106276a074SBorislav Petkov select PARAVIRT_CLOCK 811a1c4423bSMarcelo Tosatti select ARCH_CPUIDLE_HALTPOLL 812b1d40575SVitaly Kuznetsov select X86_HV_CALLBACK_VECTOR 8136276a074SBorislav Petkov default y 814a7f7f624SMasahiro Yamada help 8156276a074SBorislav Petkov This option enables various optimizations for running under the KVM 8166276a074SBorislav Petkov hypervisor. It includes a paravirtualized clock, so that instead 8176276a074SBorislav Petkov of relying on a PIT (or probably other) emulation by the 8186276a074SBorislav Petkov underlying device model, the host provides the guest with 8196276a074SBorislav Petkov timing infrastructure such as time of day, and system time 8206276a074SBorislav Petkov 821a1c4423bSMarcelo Tosatticonfig ARCH_CPUIDLE_HALTPOLL 822a1c4423bSMarcelo Tosatti def_bool n 823a1c4423bSMarcelo Tosatti prompt "Disable host haltpoll when loading haltpoll driver" 824a1c4423bSMarcelo Tosatti help 825a1c4423bSMarcelo Tosatti If virtualized under KVM, disable host haltpoll. 826a1c4423bSMarcelo Tosatti 8277733607fSMaran Wilsonconfig PVH 8287733607fSMaran Wilson bool "Support for running PVH guests" 829a7f7f624SMasahiro Yamada help 8307733607fSMaran Wilson This option enables the PVH entry point for guest virtual machines 8317733607fSMaran Wilson as specified in the x86/HVM direct boot ABI. 8327733607fSMaran Wilson 8336276a074SBorislav Petkovconfig PARAVIRT_TIME_ACCOUNTING 8346276a074SBorislav Petkov bool "Paravirtual steal time accounting" 8356276a074SBorislav Petkov depends on PARAVIRT 836a7f7f624SMasahiro Yamada help 8376276a074SBorislav Petkov Select this option to enable fine granularity task steal time 8386276a074SBorislav Petkov accounting. Time spent executing other tasks in parallel with 8396276a074SBorislav Petkov the current vCPU is discounted from the vCPU power. To account for 8406276a074SBorislav Petkov that, there can be a small performance impact. 8416276a074SBorislav Petkov 8426276a074SBorislav Petkov If in doubt, say N here. 8436276a074SBorislav Petkov 8447af192c9SGerd Hoffmannconfig PARAVIRT_CLOCK 8457af192c9SGerd Hoffmann bool 8467af192c9SGerd Hoffmann 8474a362601SJan Kiszkaconfig JAILHOUSE_GUEST 8484a362601SJan Kiszka bool "Jailhouse non-root cell support" 849abde587bSArnd Bergmann depends on X86_64 && PCI 85087e65d05SJan Kiszka select X86_PM_TIMER 851a7f7f624SMasahiro Yamada help 8524a362601SJan Kiszka This option allows to run Linux as guest in a Jailhouse non-root 8534a362601SJan Kiszka cell. You can leave this option disabled if you only want to start 8544a362601SJan Kiszka Jailhouse and run Linux afterwards in the root cell. 8554a362601SJan Kiszka 856ec7972c9SZhao Yakuiconfig ACRN_GUEST 857ec7972c9SZhao Yakui bool "ACRN Guest support" 858ec7972c9SZhao Yakui depends on X86_64 859498ad393SZhao Yakui select X86_HV_CALLBACK_VECTOR 860ec7972c9SZhao Yakui help 861ec7972c9SZhao Yakui This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 862ec7972c9SZhao Yakui a flexible, lightweight reference open-source hypervisor, built with 863ec7972c9SZhao Yakui real-time and safety-criticality in mind. It is built for embedded 864ec7972c9SZhao Yakui IOT with small footprint and real-time features. More details can be 865ec7972c9SZhao Yakui found in https://projectacrn.org/. 866ec7972c9SZhao Yakui 8676276a074SBorislav Petkovendif #HYPERVISOR_GUEST 86897349135SJeremy Fitzhardinge 869506f1d07SSam Ravnborgsource "arch/x86/Kconfig.cpu" 870506f1d07SSam Ravnborg 871506f1d07SSam Ravnborgconfig HPET_TIMER 8723c2362e6SHarvey Harrison def_bool X86_64 873506f1d07SSam Ravnborg prompt "HPET Timer Support" if X86_32 874a7f7f624SMasahiro Yamada help 875506f1d07SSam Ravnborg Use the IA-PC HPET (High Precision Event Timer) to manage 876506f1d07SSam Ravnborg time in preference to the PIT and RTC, if a HPET is 877506f1d07SSam Ravnborg present. 878506f1d07SSam Ravnborg HPET is the next generation timer replacing legacy 8254s. 879506f1d07SSam Ravnborg The HPET provides a stable time base on SMP 880506f1d07SSam Ravnborg systems, unlike the TSC, but it is more expensive to access, 8814e7f9df2SMichael S. Tsirkin as it is off-chip. The interface used is documented 8824e7f9df2SMichael S. Tsirkin in the HPET spec, revision 1. 883506f1d07SSam Ravnborg 884506f1d07SSam Ravnborg You can safely choose Y here. However, HPET will only be 885506f1d07SSam Ravnborg activated if the platform and the BIOS support this feature. 886506f1d07SSam Ravnborg Otherwise the 8254 will be used for timing services. 887506f1d07SSam Ravnborg 888506f1d07SSam Ravnborg Choose N to continue using the legacy 8254 timer. 889506f1d07SSam Ravnborg 890506f1d07SSam Ravnborgconfig HPET_EMULATE_RTC 8913c2362e6SHarvey Harrison def_bool y 8929d8af78bSBernhard Walle depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 893506f1d07SSam Ravnborg 8946a108a14SDavid Rientjes# Mark as expert because too many people got it wrong. 895506f1d07SSam Ravnborg# The code disables itself when not needed. 8967ae9392cSThomas Petazzoniconfig DMI 8977ae9392cSThomas Petazzoni default y 898cf074402SArd Biesheuvel select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 8996a108a14SDavid Rientjes bool "Enable DMI scanning" if EXPERT 900a7f7f624SMasahiro Yamada help 9017ae9392cSThomas Petazzoni Enabled scanning of DMI to identify machine quirks. Say Y 9027ae9392cSThomas Petazzoni here unless you have verified that your setup is not 9037ae9392cSThomas Petazzoni affected by entries in the DMI blacklist. Required by PNP 9047ae9392cSThomas Petazzoni BIOS code. 9057ae9392cSThomas Petazzoni 906506f1d07SSam Ravnborgconfig GART_IOMMU 90738901f1cSAndi Kleen bool "Old AMD GART IOMMU support" 9082f9237d4SChristoph Hellwig select DMA_OPS 909a4ce5a48SChristoph Hellwig select IOMMU_HELPER 910506f1d07SSam Ravnborg select SWIOTLB 91123ac4ae8SAndreas Herrmann depends on X86_64 && PCI && AMD_NB 912a7f7f624SMasahiro Yamada help 913ced3c42cSIngo Molnar Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 914ced3c42cSIngo Molnar GART based hardware IOMMUs. 915ced3c42cSIngo Molnar 916ced3c42cSIngo Molnar The GART supports full DMA access for devices with 32-bit access 917ced3c42cSIngo Molnar limitations, on systems with more than 3 GB. This is usually needed 918ced3c42cSIngo Molnar for USB, sound, many IDE/SATA chipsets and some other devices. 919ced3c42cSIngo Molnar 920ced3c42cSIngo Molnar Newer systems typically have a modern AMD IOMMU, supported via 921ced3c42cSIngo Molnar the CONFIG_AMD_IOMMU=y config option. 922ced3c42cSIngo Molnar 923ced3c42cSIngo Molnar In normal configurations this driver is only active when needed: 924ced3c42cSIngo Molnar there's more than 3 GB of memory and the system contains a 925ced3c42cSIngo Molnar 32-bit limited device. 926ced3c42cSIngo Molnar 927ced3c42cSIngo Molnar If unsure, say Y. 928506f1d07SSam Ravnborg 9291184dc2fSMike Travisconfig MAXSMP 930ddb0c5a6SSamuel Thibault bool "Enable Maximum number of SMP Processors and NUMA Nodes" 9316ea30386SKees Cook depends on X86_64 && SMP && DEBUG_KERNEL 93236f5101aSMike Travis select CPUMASK_OFFSTACK 933a7f7f624SMasahiro Yamada help 934ddb0c5a6SSamuel Thibault Enable maximum number of CPUS and NUMA Nodes for this architecture. 9351184dc2fSMike Travis If unsure, say N. 936506f1d07SSam Ravnborg 937aec6487eSIngo Molnar# 938aec6487eSIngo Molnar# The maximum number of CPUs supported: 939aec6487eSIngo Molnar# 940aec6487eSIngo Molnar# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 941aec6487eSIngo Molnar# and which can be configured interactively in the 942aec6487eSIngo Molnar# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 943aec6487eSIngo Molnar# 944aec6487eSIngo Molnar# The ranges are different on 32-bit and 64-bit kernels, depending on 945aec6487eSIngo Molnar# hardware capabilities and scalability features of the kernel. 946aec6487eSIngo Molnar# 947aec6487eSIngo Molnar# ( If MAXSMP is enabled we just use the highest possible value and disable 948aec6487eSIngo Molnar# interactive configuration. ) 949aec6487eSIngo Molnar# 950a0d0bb4dSRandy Dunlap 951aec6487eSIngo Molnarconfig NR_CPUS_RANGE_BEGIN 952a0d0bb4dSRandy Dunlap int 953aec6487eSIngo Molnar default NR_CPUS_RANGE_END if MAXSMP 954a0d0bb4dSRandy Dunlap default 1 if !SMP 955a0d0bb4dSRandy Dunlap default 2 956a0d0bb4dSRandy Dunlap 957aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 958a0d0bb4dSRandy Dunlap int 959a0d0bb4dSRandy Dunlap depends on X86_32 960aec6487eSIngo Molnar default 64 if SMP && X86_BIGSMP 961aec6487eSIngo Molnar default 8 if SMP && !X86_BIGSMP 962a0d0bb4dSRandy Dunlap default 1 if !SMP 963a0d0bb4dSRandy Dunlap 964aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 965a0d0bb4dSRandy Dunlap int 966a0d0bb4dSRandy Dunlap depends on X86_64 9671edae1aeSScott Wood default 8192 if SMP && CPUMASK_OFFSTACK 9681edae1aeSScott Wood default 512 if SMP && !CPUMASK_OFFSTACK 969a0d0bb4dSRandy Dunlap default 1 if !SMP 970aec6487eSIngo Molnar 971aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 972aec6487eSIngo Molnar int 973aec6487eSIngo Molnar depends on X86_32 974aec6487eSIngo Molnar default 32 if X86_BIGSMP 975aec6487eSIngo Molnar default 8 if SMP 976aec6487eSIngo Molnar default 1 if !SMP 977aec6487eSIngo Molnar 978aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 979aec6487eSIngo Molnar int 980aec6487eSIngo Molnar depends on X86_64 981a0d0bb4dSRandy Dunlap default 8192 if MAXSMP 982a0d0bb4dSRandy Dunlap default 64 if SMP 983aec6487eSIngo Molnar default 1 if !SMP 984a0d0bb4dSRandy Dunlap 985506f1d07SSam Ravnborgconfig NR_CPUS 98636f5101aSMike Travis int "Maximum number of CPUs" if SMP && !MAXSMP 987aec6487eSIngo Molnar range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 988aec6487eSIngo Molnar default NR_CPUS_DEFAULT 989a7f7f624SMasahiro Yamada help 990506f1d07SSam Ravnborg This allows you to specify the maximum number of CPUs which this 991bb61ccc7SJosh Boyer kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 992cad14bb9SKirill A. Shutemov supported value is 8192, otherwise the maximum value is 512. The 993506f1d07SSam Ravnborg minimum value which makes sense is 2. 994506f1d07SSam Ravnborg 995aec6487eSIngo Molnar This is purely to save memory: each supported CPU adds about 8KB 996aec6487eSIngo Molnar to the kernel image. 997506f1d07SSam Ravnborg 998506f1d07SSam Ravnborgconfig SCHED_SMT 999dbe73364SThomas Gleixner def_bool y if SMP 1000506f1d07SSam Ravnborg 1001506f1d07SSam Ravnborgconfig SCHED_MC 10023c2362e6SHarvey Harrison def_bool y 10033c2362e6SHarvey Harrison prompt "Multi-core scheduler support" 1004c8e56d20SBorislav Petkov depends on SMP 1005a7f7f624SMasahiro Yamada help 1006506f1d07SSam Ravnborg Multi-core scheduler support improves the CPU scheduler's decision 1007506f1d07SSam Ravnborg making when dealing with multi-core CPU chips at a cost of slightly 1008506f1d07SSam Ravnborg increased overhead in some places. If unsure say N here. 1009506f1d07SSam Ravnborg 1010de966cf4STim Chenconfig SCHED_MC_PRIO 1011de966cf4STim Chen bool "CPU core priorities scheduler support" 10120a21fc12SIngo Molnar depends on SCHED_MC && CPU_SUP_INTEL 10130a21fc12SIngo Molnar select X86_INTEL_PSTATE 10140a21fc12SIngo Molnar select CPU_FREQ 1015de966cf4STim Chen default y 1016a7f7f624SMasahiro Yamada help 1017de966cf4STim Chen Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1018de966cf4STim Chen core ordering determined at manufacturing time, which allows 1019de966cf4STim Chen certain cores to reach higher turbo frequencies (when running 1020de966cf4STim Chen single threaded workloads) than others. 1021de966cf4STim Chen 1022de966cf4STim Chen Enabling this kernel feature teaches the scheduler about 1023de966cf4STim Chen the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1024de966cf4STim Chen scheduler's CPU selection logic accordingly, so that higher 1025de966cf4STim Chen overall system performance can be achieved. 1026de966cf4STim Chen 1027de966cf4STim Chen This feature will have no effect on CPUs without this feature. 1028de966cf4STim Chen 1029de966cf4STim Chen If unsure say Y here. 10305e76b2abSTim Chen 103130b8b006SThomas Gleixnerconfig UP_LATE_INIT 103230b8b006SThomas Gleixner def_bool y 1033ba360f88SThomas Gleixner depends on !SMP && X86_LOCAL_APIC 103430b8b006SThomas Gleixner 1035506f1d07SSam Ravnborgconfig X86_UP_APIC 103650849eefSJan Beulich bool "Local APIC support on uniprocessors" if !PCI_MSI 103750849eefSJan Beulich default PCI_MSI 103838a1dfdaSBryan O'Donoghue depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1039a7f7f624SMasahiro Yamada help 1040506f1d07SSam Ravnborg A local APIC (Advanced Programmable Interrupt Controller) is an 1041506f1d07SSam Ravnborg integrated interrupt controller in the CPU. If you have a single-CPU 1042506f1d07SSam Ravnborg system which has a processor with a local APIC, you can say Y here to 1043506f1d07SSam Ravnborg enable and use it. If you say Y here even though your machine doesn't 1044506f1d07SSam Ravnborg have a local APIC, then the kernel will still run with no slowdown at 1045506f1d07SSam Ravnborg all. The local APIC supports CPU-generated self-interrupts (timer, 1046506f1d07SSam Ravnborg performance counters), and the NMI watchdog which detects hard 1047506f1d07SSam Ravnborg lockups. 1048506f1d07SSam Ravnborg 1049506f1d07SSam Ravnborgconfig X86_UP_IOAPIC 1050506f1d07SSam Ravnborg bool "IO-APIC support on uniprocessors" 1051506f1d07SSam Ravnborg depends on X86_UP_APIC 1052a7f7f624SMasahiro Yamada help 1053506f1d07SSam Ravnborg An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1054506f1d07SSam Ravnborg SMP-capable replacement for PC-style interrupt controllers. Most 1055506f1d07SSam Ravnborg SMP systems and many recent uniprocessor systems have one. 1056506f1d07SSam Ravnborg 1057506f1d07SSam Ravnborg If you have a single-CPU system with an IO-APIC, you can say Y here 1058506f1d07SSam Ravnborg to use it. If you say Y here even though your machine doesn't have 1059506f1d07SSam Ravnborg an IO-APIC, then the kernel will still run with no slowdown at all. 1060506f1d07SSam Ravnborg 1061506f1d07SSam Ravnborgconfig X86_LOCAL_APIC 10623c2362e6SHarvey Harrison def_bool y 10630dbc6078SThomas Petazzoni depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1064b5dc8e6cSJiang Liu select IRQ_DOMAIN_HIERARCHY 106552f518a3SJiang Liu select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1066506f1d07SSam Ravnborg 1067506f1d07SSam Ravnborgconfig X86_IO_APIC 1068b1da1e71SJan Beulich def_bool y 1069b1da1e71SJan Beulich depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1070506f1d07SSam Ravnborg 107141b9eb26SStefan Assmannconfig X86_REROUTE_FOR_BROKEN_BOOT_IRQS 107241b9eb26SStefan Assmann bool "Reroute for broken boot IRQs" 107341b9eb26SStefan Assmann depends on X86_IO_APIC 1074a7f7f624SMasahiro Yamada help 107541b9eb26SStefan Assmann This option enables a workaround that fixes a source of 107641b9eb26SStefan Assmann spurious interrupts. This is recommended when threaded 107741b9eb26SStefan Assmann interrupt handling is used on systems where the generation of 107841b9eb26SStefan Assmann superfluous "boot interrupts" cannot be disabled. 107941b9eb26SStefan Assmann 108041b9eb26SStefan Assmann Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 108141b9eb26SStefan Assmann entry in the chipset's IO-APIC is masked (as, e.g. the RT 108241b9eb26SStefan Assmann kernel does during interrupt handling). On chipsets where this 108341b9eb26SStefan Assmann boot IRQ generation cannot be disabled, this workaround keeps 108441b9eb26SStefan Assmann the original IRQ line masked so that only the equivalent "boot 108541b9eb26SStefan Assmann IRQ" is delivered to the CPUs. The workaround also tells the 108641b9eb26SStefan Assmann kernel to set up the IRQ handler on the boot IRQ line. In this 108741b9eb26SStefan Assmann way only one interrupt is delivered to the kernel. Otherwise 108841b9eb26SStefan Assmann the spurious second interrupt may cause the kernel to bring 108941b9eb26SStefan Assmann down (vital) interrupt lines. 109041b9eb26SStefan Assmann 109141b9eb26SStefan Assmann Only affects "broken" chipsets. Interrupt sharing may be 109241b9eb26SStefan Assmann increased on these systems. 109341b9eb26SStefan Assmann 1094506f1d07SSam Ravnborgconfig X86_MCE 1095bab9bc65SAndi Kleen bool "Machine Check / overheating reporting" 1096648ed940SChen, Gong select GENERIC_ALLOCATOR 1097e57dbaf7SBorislav Petkov default y 1098a7f7f624SMasahiro Yamada help 1099bab9bc65SAndi Kleen Machine Check support allows the processor to notify the 1100bab9bc65SAndi Kleen kernel if it detects a problem (e.g. overheating, data corruption). 1101506f1d07SSam Ravnborg The action the kernel takes depends on the severity of the problem, 1102bab9bc65SAndi Kleen ranging from warning messages to halting the machine. 11034efc0670SAndi Kleen 11045de97c9fSTony Luckconfig X86_MCELOG_LEGACY 11055de97c9fSTony Luck bool "Support for deprecated /dev/mcelog character device" 11065de97c9fSTony Luck depends on X86_MCE 1107a7f7f624SMasahiro Yamada help 11085de97c9fSTony Luck Enable support for /dev/mcelog which is needed by the old mcelog 11095de97c9fSTony Luck userspace logging daemon. Consider switching to the new generation 11105de97c9fSTony Luck rasdaemon solution. 11115de97c9fSTony Luck 1112506f1d07SSam Ravnborgconfig X86_MCE_INTEL 11133c2362e6SHarvey Harrison def_bool y 11143c2362e6SHarvey Harrison prompt "Intel MCE features" 1115c1ebf835SAndi Kleen depends on X86_MCE && X86_LOCAL_APIC 1116a7f7f624SMasahiro Yamada help 1117506f1d07SSam Ravnborg Additional support for intel specific MCE features such as 1118506f1d07SSam Ravnborg the thermal monitor. 1119506f1d07SSam Ravnborg 1120506f1d07SSam Ravnborgconfig X86_MCE_AMD 11213c2362e6SHarvey Harrison def_bool y 11223c2362e6SHarvey Harrison prompt "AMD MCE features" 1123f5382de9SYazen Ghannam depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1124a7f7f624SMasahiro Yamada help 1125506f1d07SSam Ravnborg Additional support for AMD specific MCE features such as 1126506f1d07SSam Ravnborg the DRAM Error Threshold. 1127506f1d07SSam Ravnborg 11284efc0670SAndi Kleenconfig X86_ANCIENT_MCE 11296fc108a0SJan Beulich bool "Support for old Pentium 5 / WinChip machine checks" 1130c31d9633SAndi Kleen depends on X86_32 && X86_MCE 1131a7f7f624SMasahiro Yamada help 11324efc0670SAndi Kleen Include support for machine check handling on old Pentium 5 or WinChip 11335065a706SMasanari Iida systems. These typically need to be enabled explicitly on the command 11344efc0670SAndi Kleen line. 11354efc0670SAndi Kleen 1136b2762686SAndi Kleenconfig X86_MCE_THRESHOLD 1137b2762686SAndi Kleen depends on X86_MCE_AMD || X86_MCE_INTEL 11386fc108a0SJan Beulich def_bool y 1139b2762686SAndi Kleen 1140ea149b36SAndi Kleenconfig X86_MCE_INJECT 1141bc8e80d5SBorislav Petkov depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1142ea149b36SAndi Kleen tristate "Machine check injector support" 1143a7f7f624SMasahiro Yamada help 1144ea149b36SAndi Kleen Provide support for injecting machine checks for testing purposes. 1145ea149b36SAndi Kleen If you don't know what a machine check is and you don't do kernel 1146ea149b36SAndi Kleen QA it is safe to say n. 1147ea149b36SAndi Kleen 11484efc0670SAndi Kleenconfig X86_THERMAL_VECTOR 11494efc0670SAndi Kleen def_bool y 11505bb38adcSAndi Kleen depends on X86_MCE_INTEL 11514efc0670SAndi Kleen 115207dc900eSPeter Zijlstrasource "arch/x86/events/Kconfig" 1153e633c65aSKan Liang 11545aef51c3SAndy Lutomirskiconfig X86_LEGACY_VM86 11551e642812SIngo Molnar bool "Legacy VM86 support" 1156506f1d07SSam Ravnborg depends on X86_32 1157a7f7f624SMasahiro Yamada help 11585aef51c3SAndy Lutomirski This option allows user programs to put the CPU into V8086 11595aef51c3SAndy Lutomirski mode, which is an 80286-era approximation of 16-bit real mode. 11605aef51c3SAndy Lutomirski 11615aef51c3SAndy Lutomirski Some very old versions of X and/or vbetool require this option 11625aef51c3SAndy Lutomirski for user mode setting. Similarly, DOSEMU will use it if 11635aef51c3SAndy Lutomirski available to accelerate real mode DOS programs. However, any 11645aef51c3SAndy Lutomirski recent version of DOSEMU, X, or vbetool should be fully 11655aef51c3SAndy Lutomirski functional even without kernel VM86 support, as they will all 11661e642812SIngo Molnar fall back to software emulation. Nevertheless, if you are using 11671e642812SIngo Molnar a 16-bit DOS program where 16-bit performance matters, vm86 11681e642812SIngo Molnar mode might be faster than emulation and you might want to 11691e642812SIngo Molnar enable this option. 11705aef51c3SAndy Lutomirski 11711e642812SIngo Molnar Note that any app that works on a 64-bit kernel is unlikely to 11721e642812SIngo Molnar need this option, as 64-bit kernels don't, and can't, support 11731e642812SIngo Molnar V8086 mode. This option is also unrelated to 16-bit protected 11741e642812SIngo Molnar mode and is not needed to run most 16-bit programs under Wine. 11755aef51c3SAndy Lutomirski 11761e642812SIngo Molnar Enabling this option increases the complexity of the kernel 11771e642812SIngo Molnar and slows down exception handling a tiny bit. 11785aef51c3SAndy Lutomirski 11791e642812SIngo Molnar If unsure, say N here. 11805aef51c3SAndy Lutomirski 11815aef51c3SAndy Lutomirskiconfig VM86 11825aef51c3SAndy Lutomirski bool 11835aef51c3SAndy Lutomirski default X86_LEGACY_VM86 118434273f41SH. Peter Anvin 118534273f41SH. Peter Anvinconfig X86_16BIT 118634273f41SH. Peter Anvin bool "Enable support for 16-bit segments" if EXPERT 118734273f41SH. Peter Anvin default y 1188a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 1189a7f7f624SMasahiro Yamada help 119034273f41SH. Peter Anvin This option is required by programs like Wine to run 16-bit 119134273f41SH. Peter Anvin protected mode legacy code on x86 processors. Disabling 119234273f41SH. Peter Anvin this option saves about 300 bytes on i386, or around 6K text 119334273f41SH. Peter Anvin plus 16K runtime memory on x86-64, 119434273f41SH. Peter Anvin 119534273f41SH. Peter Anvinconfig X86_ESPFIX32 119634273f41SH. Peter Anvin def_bool y 119734273f41SH. Peter Anvin depends on X86_16BIT && X86_32 1198506f1d07SSam Ravnborg 1199197725deSH. Peter Anvinconfig X86_ESPFIX64 1200197725deSH. Peter Anvin def_bool y 120134273f41SH. Peter Anvin depends on X86_16BIT && X86_64 1202506f1d07SSam Ravnborg 12031ad83c85SAndy Lutomirskiconfig X86_VSYSCALL_EMULATION 12041ad83c85SAndy Lutomirski bool "Enable vsyscall emulation" if EXPERT 12051ad83c85SAndy Lutomirski default y 12061ad83c85SAndy Lutomirski depends on X86_64 1207a7f7f624SMasahiro Yamada help 12081ad83c85SAndy Lutomirski This enables emulation of the legacy vsyscall page. Disabling 12091ad83c85SAndy Lutomirski it is roughly equivalent to booting with vsyscall=none, except 12101ad83c85SAndy Lutomirski that it will also disable the helpful warning if a program 12111ad83c85SAndy Lutomirski tries to use a vsyscall. With this option set to N, offending 12121ad83c85SAndy Lutomirski programs will just segfault, citing addresses of the form 12131ad83c85SAndy Lutomirski 0xffffffffff600?00. 12141ad83c85SAndy Lutomirski 12151ad83c85SAndy Lutomirski This option is required by many programs built before 2013, and 12161ad83c85SAndy Lutomirski care should be used even with newer programs if set to N. 12171ad83c85SAndy Lutomirski 12181ad83c85SAndy Lutomirski Disabling this option saves about 7K of kernel size and 12191ad83c85SAndy Lutomirski possibly 4K of additional runtime pagetable memory. 12201ad83c85SAndy Lutomirski 1221111e7b15SThomas Gleixnerconfig X86_IOPL_IOPERM 1222111e7b15SThomas Gleixner bool "IOPERM and IOPL Emulation" 1223a24ca997SThomas Gleixner default y 1224a7f7f624SMasahiro Yamada help 1225111e7b15SThomas Gleixner This enables the ioperm() and iopl() syscalls which are necessary 1226111e7b15SThomas Gleixner for legacy applications. 1227111e7b15SThomas Gleixner 1228c8137aceSThomas Gleixner Legacy IOPL support is an overbroad mechanism which allows user 1229c8137aceSThomas Gleixner space aside of accessing all 65536 I/O ports also to disable 1230c8137aceSThomas Gleixner interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1231c8137aceSThomas Gleixner capabilities and permission from potentially active security 1232c8137aceSThomas Gleixner modules. 1233c8137aceSThomas Gleixner 1234c8137aceSThomas Gleixner The emulation restricts the functionality of the syscall to 1235c8137aceSThomas Gleixner only allowing the full range I/O port access, but prevents the 1236a24ca997SThomas Gleixner ability to disable interrupts from user space which would be 1237a24ca997SThomas Gleixner granted if the hardware IOPL mechanism would be used. 1238c8137aceSThomas Gleixner 1239506f1d07SSam Ravnborgconfig TOSHIBA 1240506f1d07SSam Ravnborg tristate "Toshiba Laptop support" 1241506f1d07SSam Ravnborg depends on X86_32 1242a7f7f624SMasahiro Yamada help 1243506f1d07SSam Ravnborg This adds a driver to safely access the System Management Mode of 1244506f1d07SSam Ravnborg the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1245506f1d07SSam Ravnborg not work on models with a Phoenix BIOS. The System Management Mode 1246506f1d07SSam Ravnborg is used to set the BIOS and power saving options on Toshiba portables. 1247506f1d07SSam Ravnborg 1248506f1d07SSam Ravnborg For information on utilities to make use of this driver see the 1249506f1d07SSam Ravnborg Toshiba Linux utilities web site at: 1250506f1d07SSam Ravnborg <http://www.buzzard.org.uk/toshiba/>. 1251506f1d07SSam Ravnborg 1252506f1d07SSam Ravnborg Say Y if you intend to run this kernel on a Toshiba portable. 1253506f1d07SSam Ravnborg Say N otherwise. 1254506f1d07SSam Ravnborg 1255506f1d07SSam Ravnborgconfig I8K 1256039ae585SPali Rohár tristate "Dell i8k legacy laptop support" 1257949a9d70SJean Delvare select HWMON 1258039ae585SPali Rohár select SENSORS_DELL_SMM 1259a7f7f624SMasahiro Yamada help 1260039ae585SPali Rohár This option enables legacy /proc/i8k userspace interface in hwmon 1261039ae585SPali Rohár dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1262039ae585SPali Rohár temperature and allows controlling fan speeds of Dell laptops via 1263039ae585SPali Rohár System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1264039ae585SPali Rohár it reports also power and hotkey status. For fan speed control is 1265039ae585SPali Rohár needed userspace package i8kutils. 1266506f1d07SSam Ravnborg 1267039ae585SPali Rohár Say Y if you intend to run this kernel on old Dell laptops or want to 1268039ae585SPali Rohár use userspace package i8kutils. 1269506f1d07SSam Ravnborg Say N otherwise. 1270506f1d07SSam Ravnborg 1271506f1d07SSam Ravnborgconfig X86_REBOOTFIXUPS 12729ba16087SJan Beulich bool "Enable X86 board specific fixups for reboot" 12739ba16087SJan Beulich depends on X86_32 1274a7f7f624SMasahiro Yamada help 1275506f1d07SSam Ravnborg This enables chipset and/or board specific fixups to be done 1276506f1d07SSam Ravnborg in order to get reboot to work correctly. This is only needed on 1277506f1d07SSam Ravnborg some combinations of hardware and BIOS. The symptom, for which 1278506f1d07SSam Ravnborg this config is intended, is when reboot ends with a stalled/hung 1279506f1d07SSam Ravnborg system. 1280506f1d07SSam Ravnborg 1281506f1d07SSam Ravnborg Currently, the only fixup is for the Geode machines using 12825e3a77e9SFlorian Fainelli CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1283506f1d07SSam Ravnborg 1284506f1d07SSam Ravnborg Say Y if you want to enable the fixup. Currently, it's safe to 1285506f1d07SSam Ravnborg enable this option even if you don't need it. 1286506f1d07SSam Ravnborg Say N otherwise. 1287506f1d07SSam Ravnborg 1288506f1d07SSam Ravnborgconfig MICROCODE 12899a2bc335SBorislav Petkov bool "CPU microcode loading support" 12909a2bc335SBorislav Petkov default y 129180030e3dSBorislav Petkov depends on CPU_SUP_AMD || CPU_SUP_INTEL 1292a7f7f624SMasahiro Yamada help 1293506f1d07SSam Ravnborg If you say Y here, you will be able to update the microcode on 12945f9c01aaSBorislav Petkov Intel and AMD processors. The Intel support is for the IA32 family, 12955f9c01aaSBorislav Petkov e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 12965f9c01aaSBorislav Petkov AMD support is for families 0x10 and later. You will obviously need 12975f9c01aaSBorislav Petkov the actual microcode binary data itself which is not shipped with 12985f9c01aaSBorislav Petkov the Linux kernel. 1299506f1d07SSam Ravnborg 13005f9c01aaSBorislav Petkov The preferred method to load microcode from a detached initrd is described 1301cb1aaebeSMauro Carvalho Chehab in Documentation/x86/microcode.rst. For that you need to enable 13025f9c01aaSBorislav Petkov CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 13035f9c01aaSBorislav Petkov initrd for microcode blobs. 1304506f1d07SSam Ravnborg 1305c508c46eSBenjamin Gilbert In addition, you can build the microcode into the kernel. For that you 1306c508c46eSBenjamin Gilbert need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1307c508c46eSBenjamin Gilbert config option. 1308506f1d07SSam Ravnborg 13098d86f390SPeter Orubaconfig MICROCODE_INTEL 1310e43f6e67SBorislav Petkov bool "Intel microcode loading support" 13118d86f390SPeter Oruba depends on MICROCODE 13128d86f390SPeter Oruba default MICROCODE 1313a7f7f624SMasahiro Yamada help 13148d86f390SPeter Oruba This options enables microcode patch loading support for Intel 13158d86f390SPeter Oruba processors. 13168d86f390SPeter Oruba 1317b8989db9SAlan For the current Intel microcode data package go to 1318b8989db9SAlan <https://downloadcenter.intel.com> and search for 1319b8989db9SAlan 'Linux Processor Microcode Data File'. 13208d86f390SPeter Oruba 132180cc9f10SPeter Orubaconfig MICROCODE_AMD 1322e43f6e67SBorislav Petkov bool "AMD microcode loading support" 132380cc9f10SPeter Oruba depends on MICROCODE 1324a7f7f624SMasahiro Yamada help 132580cc9f10SPeter Oruba If you select this option, microcode patch loading support for AMD 132680cc9f10SPeter Oruba processors will be enabled. 132780cc9f10SPeter Oruba 1328506f1d07SSam Ravnborgconfig MICROCODE_OLD_INTERFACE 1329c02f48e0SBorislav Petkov bool "Ancient loading interface (DEPRECATED)" 1330c02f48e0SBorislav Petkov default n 1331506f1d07SSam Ravnborg depends on MICROCODE 1332a7f7f624SMasahiro Yamada help 1333c02f48e0SBorislav Petkov DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1334c02f48e0SBorislav Petkov which was used by userspace tools like iucode_tool and microcode.ctl. 1335c02f48e0SBorislav Petkov It is inadequate because it runs too late to be able to properly 1336c02f48e0SBorislav Petkov load microcode on a machine and it needs special tools. Instead, you 1337c02f48e0SBorislav Petkov should've switched to the early loading method with the initrd or 1338cb1aaebeSMauro Carvalho Chehab builtin microcode by now: Documentation/x86/microcode.rst 1339506f1d07SSam Ravnborg 1340506f1d07SSam Ravnborgconfig X86_MSR 1341506f1d07SSam Ravnborg tristate "/dev/cpu/*/msr - Model-specific register support" 1342a7f7f624SMasahiro Yamada help 1343506f1d07SSam Ravnborg This device gives privileged processes access to the x86 1344506f1d07SSam Ravnborg Model-Specific Registers (MSRs). It is a character device with 1345506f1d07SSam Ravnborg major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1346506f1d07SSam Ravnborg MSR accesses are directed to a specific CPU on multi-processor 1347506f1d07SSam Ravnborg systems. 1348506f1d07SSam Ravnborg 1349506f1d07SSam Ravnborgconfig X86_CPUID 1350506f1d07SSam Ravnborg tristate "/dev/cpu/*/cpuid - CPU information support" 1351a7f7f624SMasahiro Yamada help 1352506f1d07SSam Ravnborg This device gives processes access to the x86 CPUID instruction to 1353506f1d07SSam Ravnborg be executed on a specific processor. It is a character device 1354506f1d07SSam Ravnborg with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1355506f1d07SSam Ravnborg /dev/cpu/31/cpuid. 1356506f1d07SSam Ravnborg 1357506f1d07SSam Ravnborgchoice 1358506f1d07SSam Ravnborg prompt "High Memory Support" 13596fc108a0SJan Beulich default HIGHMEM4G 1360506f1d07SSam Ravnborg depends on X86_32 1361506f1d07SSam Ravnborg 1362506f1d07SSam Ravnborgconfig NOHIGHMEM 1363506f1d07SSam Ravnborg bool "off" 1364a7f7f624SMasahiro Yamada help 1365506f1d07SSam Ravnborg Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1366506f1d07SSam Ravnborg However, the address space of 32-bit x86 processors is only 4 1367506f1d07SSam Ravnborg Gigabytes large. That means that, if you have a large amount of 1368506f1d07SSam Ravnborg physical memory, not all of it can be "permanently mapped" by the 1369506f1d07SSam Ravnborg kernel. The physical memory that's not permanently mapped is called 1370506f1d07SSam Ravnborg "high memory". 1371506f1d07SSam Ravnborg 1372506f1d07SSam Ravnborg If you are compiling a kernel which will never run on a machine with 1373506f1d07SSam Ravnborg more than 1 Gigabyte total physical RAM, answer "off" here (default 1374506f1d07SSam Ravnborg choice and suitable for most users). This will result in a "3GB/1GB" 1375506f1d07SSam Ravnborg split: 3GB are mapped so that each process sees a 3GB virtual memory 1376506f1d07SSam Ravnborg space and the remaining part of the 4GB virtual memory space is used 1377506f1d07SSam Ravnborg by the kernel to permanently map as much physical memory as 1378506f1d07SSam Ravnborg possible. 1379506f1d07SSam Ravnborg 1380506f1d07SSam Ravnborg If the machine has between 1 and 4 Gigabytes physical RAM, then 1381506f1d07SSam Ravnborg answer "4GB" here. 1382506f1d07SSam Ravnborg 1383506f1d07SSam Ravnborg If more than 4 Gigabytes is used then answer "64GB" here. This 1384506f1d07SSam Ravnborg selection turns Intel PAE (Physical Address Extension) mode on. 1385506f1d07SSam Ravnborg PAE implements 3-level paging on IA32 processors. PAE is fully 1386506f1d07SSam Ravnborg supported by Linux, PAE mode is implemented on all recent Intel 1387506f1d07SSam Ravnborg processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1388506f1d07SSam Ravnborg then the kernel will not boot on CPUs that don't support PAE! 1389506f1d07SSam Ravnborg 1390506f1d07SSam Ravnborg The actual amount of total physical memory will either be 1391506f1d07SSam Ravnborg auto detected or can be forced by using a kernel command line option 1392506f1d07SSam Ravnborg such as "mem=256M". (Try "man bootparam" or see the documentation of 1393506f1d07SSam Ravnborg your boot loader (lilo or loadlin) about how to pass options to the 1394506f1d07SSam Ravnborg kernel at boot time.) 1395506f1d07SSam Ravnborg 1396506f1d07SSam Ravnborg If unsure, say "off". 1397506f1d07SSam Ravnborg 1398506f1d07SSam Ravnborgconfig HIGHMEM4G 1399506f1d07SSam Ravnborg bool "4GB" 1400a7f7f624SMasahiro Yamada help 1401506f1d07SSam Ravnborg Select this if you have a 32-bit processor and between 1 and 4 1402506f1d07SSam Ravnborg gigabytes of physical RAM. 1403506f1d07SSam Ravnborg 1404506f1d07SSam Ravnborgconfig HIGHMEM64G 1405506f1d07SSam Ravnborg bool "64GB" 140669b8d3fcSMatthew Whitehead depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1407506f1d07SSam Ravnborg select X86_PAE 1408a7f7f624SMasahiro Yamada help 1409506f1d07SSam Ravnborg Select this if you have a 32-bit processor and more than 4 1410506f1d07SSam Ravnborg gigabytes of physical RAM. 1411506f1d07SSam Ravnborg 1412506f1d07SSam Ravnborgendchoice 1413506f1d07SSam Ravnborg 1414506f1d07SSam Ravnborgchoice 14156a108a14SDavid Rientjes prompt "Memory split" if EXPERT 1416506f1d07SSam Ravnborg default VMSPLIT_3G 1417506f1d07SSam Ravnborg depends on X86_32 1418a7f7f624SMasahiro Yamada help 1419506f1d07SSam Ravnborg Select the desired split between kernel and user memory. 1420506f1d07SSam Ravnborg 1421506f1d07SSam Ravnborg If the address range available to the kernel is less than the 1422506f1d07SSam Ravnborg physical memory installed, the remaining memory will be available 1423506f1d07SSam Ravnborg as "high memory". Accessing high memory is a little more costly 1424506f1d07SSam Ravnborg than low memory, as it needs to be mapped into the kernel first. 1425506f1d07SSam Ravnborg Note that increasing the kernel address space limits the range 1426506f1d07SSam Ravnborg available to user programs, making the address space there 1427506f1d07SSam Ravnborg tighter. Selecting anything other than the default 3G/1G split 1428506f1d07SSam Ravnborg will also likely make your kernel incompatible with binary-only 1429506f1d07SSam Ravnborg kernel modules. 1430506f1d07SSam Ravnborg 1431506f1d07SSam Ravnborg If you are not absolutely sure what you are doing, leave this 1432506f1d07SSam Ravnborg option alone! 1433506f1d07SSam Ravnborg 1434506f1d07SSam Ravnborg config VMSPLIT_3G 1435506f1d07SSam Ravnborg bool "3G/1G user/kernel split" 1436506f1d07SSam Ravnborg config VMSPLIT_3G_OPT 1437506f1d07SSam Ravnborg depends on !X86_PAE 1438506f1d07SSam Ravnborg bool "3G/1G user/kernel split (for full 1G low memory)" 1439506f1d07SSam Ravnborg config VMSPLIT_2G 1440506f1d07SSam Ravnborg bool "2G/2G user/kernel split" 1441506f1d07SSam Ravnborg config VMSPLIT_2G_OPT 1442506f1d07SSam Ravnborg depends on !X86_PAE 1443506f1d07SSam Ravnborg bool "2G/2G user/kernel split (for full 2G low memory)" 1444506f1d07SSam Ravnborg config VMSPLIT_1G 1445506f1d07SSam Ravnborg bool "1G/3G user/kernel split" 1446506f1d07SSam Ravnborgendchoice 1447506f1d07SSam Ravnborg 1448506f1d07SSam Ravnborgconfig PAGE_OFFSET 1449506f1d07SSam Ravnborg hex 1450506f1d07SSam Ravnborg default 0xB0000000 if VMSPLIT_3G_OPT 1451506f1d07SSam Ravnborg default 0x80000000 if VMSPLIT_2G 1452506f1d07SSam Ravnborg default 0x78000000 if VMSPLIT_2G_OPT 1453506f1d07SSam Ravnborg default 0x40000000 if VMSPLIT_1G 1454506f1d07SSam Ravnborg default 0xC0000000 1455506f1d07SSam Ravnborg depends on X86_32 1456506f1d07SSam Ravnborg 1457506f1d07SSam Ravnborgconfig HIGHMEM 14583c2362e6SHarvey Harrison def_bool y 1459506f1d07SSam Ravnborg depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1460506f1d07SSam Ravnborg 1461506f1d07SSam Ravnborgconfig X86_PAE 14629ba16087SJan Beulich bool "PAE (Physical Address Extension) Support" 1463506f1d07SSam Ravnborg depends on X86_32 && !HIGHMEM4G 1464d4a451d5SChristoph Hellwig select PHYS_ADDR_T_64BIT 14659d99c712SChristian Melki select SWIOTLB 1466a7f7f624SMasahiro Yamada help 1467506f1d07SSam Ravnborg PAE is required for NX support, and furthermore enables 1468506f1d07SSam Ravnborg larger swapspace support for non-overcommit purposes. It 1469506f1d07SSam Ravnborg has the cost of more pagetable lookup overhead, and also 1470506f1d07SSam Ravnborg consumes more pagetable space per process. 1471506f1d07SSam Ravnborg 147277ef56e4SKirill A. Shutemovconfig X86_5LEVEL 147377ef56e4SKirill A. Shutemov bool "Enable 5-level page tables support" 147418ec1eafSKirill A. Shutemov default y 1475eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 1476162434e7SKirill A. Shutemov select SPARSEMEM_VMEMMAP 147777ef56e4SKirill A. Shutemov depends on X86_64 1478a7f7f624SMasahiro Yamada help 147977ef56e4SKirill A. Shutemov 5-level paging enables access to larger address space: 148077ef56e4SKirill A. Shutemov upto 128 PiB of virtual address space and 4 PiB of 148177ef56e4SKirill A. Shutemov physical address space. 148277ef56e4SKirill A. Shutemov 148377ef56e4SKirill A. Shutemov It will be supported by future Intel CPUs. 148477ef56e4SKirill A. Shutemov 14856657fca0SKirill A. Shutemov A kernel with the option enabled can be booted on machines that 14866657fca0SKirill A. Shutemov support 4- or 5-level paging. 148777ef56e4SKirill A. Shutemov 1488cb1aaebeSMauro Carvalho Chehab See Documentation/x86/x86_64/5level-paging.rst for more 148977ef56e4SKirill A. Shutemov information. 149077ef56e4SKirill A. Shutemov 149177ef56e4SKirill A. Shutemov Say N if unsure. 149277ef56e4SKirill A. Shutemov 149310971ab2SIngo Molnarconfig X86_DIRECT_GBPAGES 1494e5008abeSLuis R. Rodriguez def_bool y 14952e1da13fSVlastimil Babka depends on X86_64 1496a7f7f624SMasahiro Yamada help 149710971ab2SIngo Molnar Certain kernel features effectively disable kernel 149810971ab2SIngo Molnar linear 1 GB mappings (even if the CPU otherwise 149910971ab2SIngo Molnar supports them), so don't confuse the user by printing 150010971ab2SIngo Molnar that we have them enabled. 15019e899816SNick Piggin 15025c280cf6SThomas Gleixnerconfig X86_CPA_STATISTICS 15035c280cf6SThomas Gleixner bool "Enable statistic for Change Page Attribute" 15045c280cf6SThomas Gleixner depends on DEBUG_FS 1505a7f7f624SMasahiro Yamada help 1506b75baaf3SIngo Molnar Expose statistics about the Change Page Attribute mechanism, which 1507a943245aSColin Ian King helps to determine the effectiveness of preserving large and huge 15085c280cf6SThomas Gleixner page mappings when mapping protections are changed. 15095c280cf6SThomas Gleixner 15107744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT 15117744ccdbSTom Lendacky bool "AMD Secure Memory Encryption (SME) support" 15127744ccdbSTom Lendacky depends on X86_64 && CPU_SUP_AMD 151382fef0adSDavid Rientjes select DMA_COHERENT_POOL 151494d49eb3SKirill A. Shutemov select DYNAMIC_PHYSICAL_MASK 1515ce9084baSArd Biesheuvel select ARCH_USE_MEMREMAP_PROT 15169087c375STom Lendacky select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1517597cfe48SJoerg Roedel select INSTRUCTION_DECODER 1518a7f7f624SMasahiro Yamada help 15197744ccdbSTom Lendacky Say yes to enable support for the encryption of system memory. 15207744ccdbSTom Lendacky This requires an AMD processor that supports Secure Memory 15217744ccdbSTom Lendacky Encryption (SME). 15227744ccdbSTom Lendacky 15237744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 15247744ccdbSTom Lendacky bool "Activate AMD Secure Memory Encryption (SME) by default" 15257744ccdbSTom Lendacky default y 15267744ccdbSTom Lendacky depends on AMD_MEM_ENCRYPT 1527a7f7f624SMasahiro Yamada help 15287744ccdbSTom Lendacky Say yes to have system memory encrypted by default if running on 15297744ccdbSTom Lendacky an AMD processor that supports Secure Memory Encryption (SME). 15307744ccdbSTom Lendacky 15317744ccdbSTom Lendacky If set to Y, then the encryption of system memory can be 15327744ccdbSTom Lendacky deactivated with the mem_encrypt=off command line option. 15337744ccdbSTom Lendacky 15347744ccdbSTom Lendacky If set to N, then the encryption of system memory can be 15357744ccdbSTom Lendacky activated with the mem_encrypt=on command line option. 15367744ccdbSTom Lendacky 1537506f1d07SSam Ravnborg# Common NUMA Features 1538506f1d07SSam Ravnborgconfig NUMA 1539e133f6eaSRandy Dunlap bool "NUMA Memory Allocation and Scheduler Support" 1540506f1d07SSam Ravnborg depends on SMP 1541b5660ba7SH. Peter Anvin depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1542b5660ba7SH. Peter Anvin default y if X86_BIGSMP 1543a7f7f624SMasahiro Yamada help 1544e133f6eaSRandy Dunlap Enable NUMA (Non-Uniform Memory Access) support. 1545fd51b2d7SKOSAKI Motohiro 1546506f1d07SSam Ravnborg The kernel will try to allocate memory used by a CPU on the 1547506f1d07SSam Ravnborg local memory controller of the CPU and add some more 1548506f1d07SSam Ravnborg NUMA awareness to the kernel. 1549506f1d07SSam Ravnborg 1550c280ea5eSIngo Molnar For 64-bit this is recommended if the system is Intel Core i7 1551fd51b2d7SKOSAKI Motohiro (or later), AMD Opteron, or EM64T NUMA. 1552fd51b2d7SKOSAKI Motohiro 1553b5660ba7SH. Peter Anvin For 32-bit this is only needed if you boot a 32-bit 15547cf6c945SDavid Rientjes kernel on a 64-bit NUMA platform. 1555fd51b2d7SKOSAKI Motohiro 1556fd51b2d7SKOSAKI Motohiro Otherwise, you should say N. 1557506f1d07SSam Ravnborg 1558eec1d4faSHans Rosenfeldconfig AMD_NUMA 15593c2362e6SHarvey Harrison def_bool y 15603c2362e6SHarvey Harrison prompt "Old style AMD Opteron NUMA detection" 15615da0ef9aSTejun Heo depends on X86_64 && NUMA && PCI 1562a7f7f624SMasahiro Yamada help 1563eec1d4faSHans Rosenfeld Enable AMD NUMA node topology detection. You should say Y here if 1564eec1d4faSHans Rosenfeld you have a multi processor AMD system. This uses an old method to 1565eec1d4faSHans Rosenfeld read the NUMA configuration directly from the builtin Northbridge 1566eec1d4faSHans Rosenfeld of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1567eec1d4faSHans Rosenfeld which also takes priority if both are compiled in. 1568506f1d07SSam Ravnborg 1569506f1d07SSam Ravnborgconfig X86_64_ACPI_NUMA 15703c2362e6SHarvey Harrison def_bool y 15713c2362e6SHarvey Harrison prompt "ACPI NUMA detection" 1572506f1d07SSam Ravnborg depends on X86_64 && NUMA && ACPI && PCI 1573506f1d07SSam Ravnborg select ACPI_NUMA 1574a7f7f624SMasahiro Yamada help 1575506f1d07SSam Ravnborg Enable ACPI SRAT based node topology detection. 1576506f1d07SSam Ravnborg 1577506f1d07SSam Ravnborgconfig NUMA_EMU 1578506f1d07SSam Ravnborg bool "NUMA emulation" 15791b7e03efSTejun Heo depends on NUMA 1580a7f7f624SMasahiro Yamada help 1581506f1d07SSam Ravnborg Enable NUMA emulation. A flat machine will be split 1582506f1d07SSam Ravnborg into virtual nodes when booted with "numa=fake=N", where N is the 1583506f1d07SSam Ravnborg number of nodes. This is only useful for debugging. 1584506f1d07SSam Ravnborg 1585506f1d07SSam Ravnborgconfig NODES_SHIFT 1586d25e26b6SLinus Torvalds int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 158751591e31SDavid Rientjes range 1 10 158851591e31SDavid Rientjes default "10" if MAXSMP 1589506f1d07SSam Ravnborg default "6" if X86_64 1590506f1d07SSam Ravnborg default "3" 1591506f1d07SSam Ravnborg depends on NEED_MULTIPLE_NODES 1592a7f7f624SMasahiro Yamada help 15931184dc2fSMike Travis Specify the maximum number of NUMA Nodes available on the target 1594692105b8SMatt LaPlante system. Increases memory reserved to accommodate various tables. 1595506f1d07SSam Ravnborg 1596506f1d07SSam Ravnborgconfig ARCH_FLATMEM_ENABLE 1597506f1d07SSam Ravnborg def_bool y 15983b16651fSTejun Heo depends on X86_32 && !NUMA 1599506f1d07SSam Ravnborg 1600506f1d07SSam Ravnborgconfig ARCH_SPARSEMEM_ENABLE 1601506f1d07SSam Ravnborg def_bool y 16026ea30386SKees Cook depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1603506f1d07SSam Ravnborg select SPARSEMEM_STATIC if X86_32 1604506f1d07SSam Ravnborg select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1605506f1d07SSam Ravnborg 16063b16651fSTejun Heoconfig ARCH_SPARSEMEM_DEFAULT 16076ad57f7fSMike Rapoport def_bool X86_64 || (NUMA && X86_32) 16083b16651fSTejun Heo 1609506f1d07SSam Ravnborgconfig ARCH_SELECT_MEMORY_MODEL 1610506f1d07SSam Ravnborg def_bool y 1611b263295dSChristoph Lameter depends on ARCH_SPARSEMEM_ENABLE 1612506f1d07SSam Ravnborg 1613506f1d07SSam Ravnborgconfig ARCH_MEMORY_PROBE 1614a0842b70SToshi Kani bool "Enable sysfs memory/probe interface" 16153120e25eSJan Beulich depends on X86_64 && MEMORY_HOTPLUG 1616a0842b70SToshi Kani help 1617a0842b70SToshi Kani This option enables a sysfs memory/probe interface for testing. 1618cb1aaebeSMauro Carvalho Chehab See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1619a0842b70SToshi Kani If you are unsure how to answer this question, answer N. 1620506f1d07SSam Ravnborg 16213b16651fSTejun Heoconfig ARCH_PROC_KCORE_TEXT 16223b16651fSTejun Heo def_bool y 16233b16651fSTejun Heo depends on X86_64 && PROC_KCORE 16243b16651fSTejun Heo 1625a29815a3SAvi Kivityconfig ILLEGAL_POINTER_VALUE 1626a29815a3SAvi Kivity hex 1627a29815a3SAvi Kivity default 0 if X86_32 1628a29815a3SAvi Kivity default 0xdead000000000000 if X86_64 1629a29815a3SAvi Kivity 16307a67832cSDan Williamsconfig X86_PMEM_LEGACY_DEVICE 16317a67832cSDan Williams bool 16327a67832cSDan Williams 1633ec776ef6SChristoph Hellwigconfig X86_PMEM_LEGACY 16347a67832cSDan Williams tristate "Support non-standard NVDIMMs and ADR protected memory" 16359f53f9faSDan Williams depends on PHYS_ADDR_T_64BIT 16369f53f9faSDan Williams depends on BLK_DEV 16377a67832cSDan Williams select X86_PMEM_LEGACY_DEVICE 16387b27a862SDan Williams select NUMA_KEEP_MEMINFO if NUMA 16399f53f9faSDan Williams select LIBNVDIMM 1640ec776ef6SChristoph Hellwig help 1641ec776ef6SChristoph Hellwig Treat memory marked using the non-standard e820 type of 12 as used 1642ec776ef6SChristoph Hellwig by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1643ec776ef6SChristoph Hellwig The kernel will offer these regions to the 'pmem' driver so 1644ec776ef6SChristoph Hellwig they can be used for persistent storage. 1645ec776ef6SChristoph Hellwig 1646ec776ef6SChristoph Hellwig Say Y if unsure. 1647ec776ef6SChristoph Hellwig 1648506f1d07SSam Ravnborgconfig HIGHPTE 1649506f1d07SSam Ravnborg bool "Allocate 3rd-level pagetables from highmem" 16506fc108a0SJan Beulich depends on HIGHMEM 1651a7f7f624SMasahiro Yamada help 1652506f1d07SSam Ravnborg The VM uses one page table entry for each page of physical memory. 1653506f1d07SSam Ravnborg For systems with a lot of RAM, this can be wasteful of precious 1654506f1d07SSam Ravnborg low memory. Setting this option will put user-space page table 1655506f1d07SSam Ravnborg entries in high memory. 1656506f1d07SSam Ravnborg 16579f077871SJeremy Fitzhardingeconfig X86_CHECK_BIOS_CORRUPTION 16589f077871SJeremy Fitzhardinge bool "Check for low memory corruption" 1659a7f7f624SMasahiro Yamada help 16609f077871SJeremy Fitzhardinge Periodically check for memory corruption in low memory, which 16619f077871SJeremy Fitzhardinge is suspected to be caused by BIOS. Even when enabled in the 16629f077871SJeremy Fitzhardinge configuration, it is disabled at runtime. Enable it by 16639f077871SJeremy Fitzhardinge setting "memory_corruption_check=1" on the kernel command 16649f077871SJeremy Fitzhardinge line. By default it scans the low 64k of memory every 60 16659f077871SJeremy Fitzhardinge seconds; see the memory_corruption_check_size and 16669f077871SJeremy Fitzhardinge memory_corruption_check_period parameters in 16678c27ceffSMauro Carvalho Chehab Documentation/admin-guide/kernel-parameters.rst to adjust this. 16689f077871SJeremy Fitzhardinge 16699f077871SJeremy Fitzhardinge When enabled with the default parameters, this option has 16709f077871SJeremy Fitzhardinge almost no overhead, as it reserves a relatively small amount 16719f077871SJeremy Fitzhardinge of memory and scans it infrequently. It both detects corruption 16729f077871SJeremy Fitzhardinge and prevents it from affecting the running system. 16739f077871SJeremy Fitzhardinge 16749f077871SJeremy Fitzhardinge It is, however, intended as a diagnostic tool; if repeatable 16759f077871SJeremy Fitzhardinge BIOS-originated corruption always affects the same memory, 16769f077871SJeremy Fitzhardinge you can use memmap= to prevent the kernel from using that 16779f077871SJeremy Fitzhardinge memory. 16789f077871SJeremy Fitzhardinge 1679c885df50SJeremy Fitzhardingeconfig X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1680c885df50SJeremy Fitzhardinge bool "Set the default setting of memory_corruption_check" 1681c885df50SJeremy Fitzhardinge depends on X86_CHECK_BIOS_CORRUPTION 1682c885df50SJeremy Fitzhardinge default y 1683a7f7f624SMasahiro Yamada help 1684c885df50SJeremy Fitzhardinge Set whether the default state of memory_corruption_check is 1685c885df50SJeremy Fitzhardinge on or off. 1686c885df50SJeremy Fitzhardinge 16879ea77bdbSH. Peter Anvinconfig X86_RESERVE_LOW 1688d0cd7425SH. Peter Anvin int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1689d0cd7425SH. Peter Anvin default 64 1690d0cd7425SH. Peter Anvin range 4 640 1691a7f7f624SMasahiro Yamada help 1692d0cd7425SH. Peter Anvin Specify the amount of low memory to reserve for the BIOS. 1693fc381519SIngo Molnar 1694d0cd7425SH. Peter Anvin The first page contains BIOS data structures that the kernel 1695d0cd7425SH. Peter Anvin must not use, so that page must always be reserved. 1696fc381519SIngo Molnar 1697d0cd7425SH. Peter Anvin By default we reserve the first 64K of physical RAM, as a 1698d0cd7425SH. Peter Anvin number of BIOSes are known to corrupt that memory range 1699d0cd7425SH. Peter Anvin during events such as suspend/resume or monitor cable 1700d0cd7425SH. Peter Anvin insertion, so it must not be used by the kernel. 1701fc381519SIngo Molnar 1702d0cd7425SH. Peter Anvin You can set this to 4 if you are absolutely sure that you 1703d0cd7425SH. Peter Anvin trust the BIOS to get all its memory reservations and usages 1704d0cd7425SH. Peter Anvin right. If you know your BIOS have problems beyond the 1705d0cd7425SH. Peter Anvin default 64K area, you can set this to 640 to avoid using the 1706d0cd7425SH. Peter Anvin entire low memory range. 1707d0cd7425SH. Peter Anvin 1708d0cd7425SH. Peter Anvin If you have doubts about the BIOS (e.g. suspend/resume does 1709d0cd7425SH. Peter Anvin not work or there's kernel crashes after certain hardware 1710d0cd7425SH. Peter Anvin hotplug events) then you might want to enable 1711d0cd7425SH. Peter Anvin X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1712d0cd7425SH. Peter Anvin typical corruption patterns. 1713d0cd7425SH. Peter Anvin 1714d0cd7425SH. Peter Anvin Leave this to the default value of 64 if you are unsure. 1715fc381519SIngo Molnar 1716506f1d07SSam Ravnborgconfig MATH_EMULATION 1717506f1d07SSam Ravnborg bool 1718a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 171987d6021bSArnd Bergmann prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1720a7f7f624SMasahiro Yamada help 1721506f1d07SSam Ravnborg Linux can emulate a math coprocessor (used for floating point 1722506f1d07SSam Ravnborg operations) if you don't have one. 486DX and Pentium processors have 1723506f1d07SSam Ravnborg a math coprocessor built in, 486SX and 386 do not, unless you added 1724506f1d07SSam Ravnborg a 487DX or 387, respectively. (The messages during boot time can 1725506f1d07SSam Ravnborg give you some hints here ["man dmesg"].) Everyone needs either a 1726506f1d07SSam Ravnborg coprocessor or this emulation. 1727506f1d07SSam Ravnborg 1728506f1d07SSam Ravnborg If you don't have a math coprocessor, you need to say Y here; if you 1729506f1d07SSam Ravnborg say Y here even though you have a coprocessor, the coprocessor will 1730506f1d07SSam Ravnborg be used nevertheless. (This behavior can be changed with the kernel 1731506f1d07SSam Ravnborg command line option "no387", which comes handy if your coprocessor 1732506f1d07SSam Ravnborg is broken. Try "man bootparam" or see the documentation of your boot 1733506f1d07SSam Ravnborg loader (lilo or loadlin) about how to pass options to the kernel at 1734506f1d07SSam Ravnborg boot time.) This means that it is a good idea to say Y here if you 1735506f1d07SSam Ravnborg intend to use this kernel on different machines. 1736506f1d07SSam Ravnborg 1737506f1d07SSam Ravnborg More information about the internals of the Linux math coprocessor 1738506f1d07SSam Ravnborg emulation can be found in <file:arch/x86/math-emu/README>. 1739506f1d07SSam Ravnborg 1740506f1d07SSam Ravnborg If you are not sure, say Y; apart from resulting in a 66 KB bigger 1741506f1d07SSam Ravnborg kernel, it won't hurt. 1742506f1d07SSam Ravnborg 1743506f1d07SSam Ravnborgconfig MTRR 17446fc108a0SJan Beulich def_bool y 17456a108a14SDavid Rientjes prompt "MTRR (Memory Type Range Register) support" if EXPERT 1746a7f7f624SMasahiro Yamada help 1747506f1d07SSam Ravnborg On Intel P6 family processors (Pentium Pro, Pentium II and later) 1748506f1d07SSam Ravnborg the Memory Type Range Registers (MTRRs) may be used to control 1749506f1d07SSam Ravnborg processor access to memory ranges. This is most useful if you have 1750506f1d07SSam Ravnborg a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1751506f1d07SSam Ravnborg allows bus write transfers to be combined into a larger transfer 1752506f1d07SSam Ravnborg before bursting over the PCI/AGP bus. This can increase performance 1753506f1d07SSam Ravnborg of image write operations 2.5 times or more. Saying Y here creates a 1754506f1d07SSam Ravnborg /proc/mtrr file which may be used to manipulate your processor's 1755506f1d07SSam Ravnborg MTRRs. Typically the X server should use this. 1756506f1d07SSam Ravnborg 1757506f1d07SSam Ravnborg This code has a reasonably generic interface so that similar 1758506f1d07SSam Ravnborg control registers on other processors can be easily supported 1759506f1d07SSam Ravnborg as well: 1760506f1d07SSam Ravnborg 1761506f1d07SSam Ravnborg The Cyrix 6x86, 6x86MX and M II processors have Address Range 1762506f1d07SSam Ravnborg Registers (ARRs) which provide a similar functionality to MTRRs. For 1763506f1d07SSam Ravnborg these, the ARRs are used to emulate the MTRRs. 1764506f1d07SSam Ravnborg The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1765506f1d07SSam Ravnborg MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1766506f1d07SSam Ravnborg write-combining. All of these processors are supported by this code 1767506f1d07SSam Ravnborg and it makes sense to say Y here if you have one of them. 1768506f1d07SSam Ravnborg 1769506f1d07SSam Ravnborg Saying Y here also fixes a problem with buggy SMP BIOSes which only 1770506f1d07SSam Ravnborg set the MTRRs for the boot CPU and not for the secondary CPUs. This 1771506f1d07SSam Ravnborg can lead to all sorts of problems, so it's good to say Y here. 1772506f1d07SSam Ravnborg 1773506f1d07SSam Ravnborg You can safely say Y even if your machine doesn't have MTRRs, you'll 1774506f1d07SSam Ravnborg just add about 9 KB to your kernel. 1775506f1d07SSam Ravnborg 1776cb1aaebeSMauro Carvalho Chehab See <file:Documentation/x86/mtrr.rst> for more information. 1777506f1d07SSam Ravnborg 177895ffa243SYinghai Luconfig MTRR_SANITIZER 17792ffb3501SYinghai Lu def_bool y 178095ffa243SYinghai Lu prompt "MTRR cleanup support" 178195ffa243SYinghai Lu depends on MTRR 1782a7f7f624SMasahiro Yamada help 1783aba3728cSThomas Gleixner Convert MTRR layout from continuous to discrete, so X drivers can 1784aba3728cSThomas Gleixner add writeback entries. 178595ffa243SYinghai Lu 1786aba3728cSThomas Gleixner Can be disabled with disable_mtrr_cleanup on the kernel command line. 1787692105b8SMatt LaPlante The largest mtrr entry size for a continuous block can be set with 1788aba3728cSThomas Gleixner mtrr_chunk_size. 178995ffa243SYinghai Lu 17902ffb3501SYinghai Lu If unsure, say Y. 179195ffa243SYinghai Lu 179295ffa243SYinghai Luconfig MTRR_SANITIZER_ENABLE_DEFAULT 1793f5098d62SYinghai Lu int "MTRR cleanup enable value (0-1)" 1794f5098d62SYinghai Lu range 0 1 1795f5098d62SYinghai Lu default "0" 179695ffa243SYinghai Lu depends on MTRR_SANITIZER 1797a7f7f624SMasahiro Yamada help 1798f5098d62SYinghai Lu Enable mtrr cleanup default value 179995ffa243SYinghai Lu 180012031a62SYinghai Luconfig MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 180112031a62SYinghai Lu int "MTRR cleanup spare reg num (0-7)" 180212031a62SYinghai Lu range 0 7 180312031a62SYinghai Lu default "1" 180412031a62SYinghai Lu depends on MTRR_SANITIZER 1805a7f7f624SMasahiro Yamada help 180612031a62SYinghai Lu mtrr cleanup spare entries default, it can be changed via 1807aba3728cSThomas Gleixner mtrr_spare_reg_nr=N on the kernel command line. 180812031a62SYinghai Lu 18092e5d9c85Svenkatesh.pallipadi@intel.comconfig X86_PAT 18106fc108a0SJan Beulich def_bool y 18116a108a14SDavid Rientjes prompt "x86 PAT support" if EXPERT 18122a8a2719SIngo Molnar depends on MTRR 1813a7f7f624SMasahiro Yamada help 18142e5d9c85Svenkatesh.pallipadi@intel.com Use PAT attributes to setup page level cache control. 1815042b78e4SVenki Pallipadi 18162e5d9c85Svenkatesh.pallipadi@intel.com PATs are the modern equivalents of MTRRs and are much more 18172e5d9c85Svenkatesh.pallipadi@intel.com flexible than MTRRs. 18182e5d9c85Svenkatesh.pallipadi@intel.com 18192e5d9c85Svenkatesh.pallipadi@intel.com Say N here if you see bootup problems (boot crash, boot hang, 1820042b78e4SVenki Pallipadi spontaneous reboots) or a non-working video driver. 18212e5d9c85Svenkatesh.pallipadi@intel.com 18222e5d9c85Svenkatesh.pallipadi@intel.com If unsure, say Y. 18232e5d9c85Svenkatesh.pallipadi@intel.com 182446cf98cdSVenkatesh Pallipadiconfig ARCH_USES_PG_UNCACHED 182546cf98cdSVenkatesh Pallipadi def_bool y 182646cf98cdSVenkatesh Pallipadi depends on X86_PAT 182746cf98cdSVenkatesh Pallipadi 1828628c6246SH. Peter Anvinconfig ARCH_RANDOM 1829628c6246SH. Peter Anvin def_bool y 1830628c6246SH. Peter Anvin prompt "x86 architectural random number generator" if EXPERT 1831a7f7f624SMasahiro Yamada help 1832628c6246SH. Peter Anvin Enable the x86 architectural RDRAND instruction 1833628c6246SH. Peter Anvin (Intel Bull Mountain technology) to generate random numbers. 1834628c6246SH. Peter Anvin If supported, this is a high bandwidth, cryptographically 1835628c6246SH. Peter Anvin secure hardware random number generator. 1836628c6246SH. Peter Anvin 183751ae4a2dSH. Peter Anvinconfig X86_SMAP 183851ae4a2dSH. Peter Anvin def_bool y 183951ae4a2dSH. Peter Anvin prompt "Supervisor Mode Access Prevention" if EXPERT 1840a7f7f624SMasahiro Yamada help 184151ae4a2dSH. Peter Anvin Supervisor Mode Access Prevention (SMAP) is a security 184251ae4a2dSH. Peter Anvin feature in newer Intel processors. There is a small 184351ae4a2dSH. Peter Anvin performance cost if this enabled and turned on; there is 184451ae4a2dSH. Peter Anvin also a small increase in the kernel size if this is enabled. 184551ae4a2dSH. Peter Anvin 184651ae4a2dSH. Peter Anvin If unsure, say Y. 184751ae4a2dSH. Peter Anvin 1848b971880fSBabu Mogerconfig X86_UMIP 1849796ebc81SRicardo Neri def_bool y 1850b971880fSBabu Moger prompt "User Mode Instruction Prevention" if EXPERT 1851a7f7f624SMasahiro Yamada help 1852b971880fSBabu Moger User Mode Instruction Prevention (UMIP) is a security feature in 1853b971880fSBabu Moger some x86 processors. If enabled, a general protection fault is 1854b971880fSBabu Moger issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1855b971880fSBabu Moger executed in user mode. These instructions unnecessarily expose 1856b971880fSBabu Moger information about the hardware state. 1857796ebc81SRicardo Neri 1858796ebc81SRicardo Neri The vast majority of applications do not use these instructions. 1859796ebc81SRicardo Neri For the very few that do, software emulation is provided in 1860796ebc81SRicardo Neri specific cases in protected and virtual-8086 modes. Emulated 1861796ebc81SRicardo Neri results are dummy. 1862aa35f896SRicardo Neri 186335e97790SDave Hansenconfig X86_INTEL_MEMORY_PROTECTION_KEYS 186438f3e775SBabu Moger prompt "Memory Protection Keys" 186535e97790SDave Hansen def_bool y 1866284244a9SDave Hansen # Note: only available in 64-bit mode 186738f3e775SBabu Moger depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 186852c8e601SIngo Molnar select ARCH_USES_HIGH_VMA_FLAGS 186952c8e601SIngo Molnar select ARCH_HAS_PKEYS 1870a7f7f624SMasahiro Yamada help 1871284244a9SDave Hansen Memory Protection Keys provides a mechanism for enforcing 1872284244a9SDave Hansen page-based protections, but without requiring modification of the 1873284244a9SDave Hansen page tables when an application changes protection domains. 1874284244a9SDave Hansen 18751eecbcdcSMauro Carvalho Chehab For details, see Documentation/core-api/protection-keys.rst 1876284244a9SDave Hansen 1877284244a9SDave Hansen If unsure, say y. 187835e97790SDave Hansen 1879db616173SMichal Hockochoice 1880db616173SMichal Hocko prompt "TSX enable mode" 1881db616173SMichal Hocko depends on CPU_SUP_INTEL 1882db616173SMichal Hocko default X86_INTEL_TSX_MODE_OFF 1883db616173SMichal Hocko help 1884db616173SMichal Hocko Intel's TSX (Transactional Synchronization Extensions) feature 1885db616173SMichal Hocko allows to optimize locking protocols through lock elision which 1886db616173SMichal Hocko can lead to a noticeable performance boost. 1887db616173SMichal Hocko 1888db616173SMichal Hocko On the other hand it has been shown that TSX can be exploited 1889db616173SMichal Hocko to form side channel attacks (e.g. TAA) and chances are there 1890db616173SMichal Hocko will be more of those attacks discovered in the future. 1891db616173SMichal Hocko 1892db616173SMichal Hocko Therefore TSX is not enabled by default (aka tsx=off). An admin 1893db616173SMichal Hocko might override this decision by tsx=on the command line parameter. 1894db616173SMichal Hocko Even with TSX enabled, the kernel will attempt to enable the best 1895db616173SMichal Hocko possible TAA mitigation setting depending on the microcode available 1896db616173SMichal Hocko for the particular machine. 1897db616173SMichal Hocko 1898db616173SMichal Hocko This option allows to set the default tsx mode between tsx=on, =off 1899db616173SMichal Hocko and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1900db616173SMichal Hocko details. 1901db616173SMichal Hocko 1902db616173SMichal Hocko Say off if not sure, auto if TSX is in use but it should be used on safe 1903db616173SMichal Hocko platforms or on if TSX is in use and the security aspect of tsx is not 1904db616173SMichal Hocko relevant. 1905db616173SMichal Hocko 1906db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_OFF 1907db616173SMichal Hocko bool "off" 1908db616173SMichal Hocko help 1909db616173SMichal Hocko TSX is disabled if possible - equals to tsx=off command line parameter. 1910db616173SMichal Hocko 1911db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_ON 1912db616173SMichal Hocko bool "on" 1913db616173SMichal Hocko help 1914db616173SMichal Hocko TSX is always enabled on TSX capable HW - equals the tsx=on command 1915db616173SMichal Hocko line parameter. 1916db616173SMichal Hocko 1917db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_AUTO 1918db616173SMichal Hocko bool "auto" 1919db616173SMichal Hocko help 1920db616173SMichal Hocko TSX is enabled on TSX capable HW that is believed to be safe against 1921db616173SMichal Hocko side channel attacks- equals the tsx=auto command line parameter. 1922db616173SMichal Hockoendchoice 1923db616173SMichal Hocko 1924e7e05452SSean Christophersonconfig X86_SGX 1925e7e05452SSean Christopherson bool "Software Guard eXtensions (SGX)" 1926e7e05452SSean Christopherson depends on X86_64 && CPU_SUP_INTEL 1927e7e05452SSean Christopherson depends on CRYPTO=y 1928e7e05452SSean Christopherson depends on CRYPTO_SHA256=y 1929e7e05452SSean Christopherson select SRCU 1930e7e05452SSean Christopherson select MMU_NOTIFIER 1931e7e05452SSean Christopherson help 1932e7e05452SSean Christopherson Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1933e7e05452SSean Christopherson that can be used by applications to set aside private regions of code 1934e7e05452SSean Christopherson and data, referred to as enclaves. An enclave's private memory can 1935e7e05452SSean Christopherson only be accessed by code running within the enclave. Accesses from 1936e7e05452SSean Christopherson outside the enclave, including other enclaves, are disallowed by 1937e7e05452SSean Christopherson hardware. 1938e7e05452SSean Christopherson 1939e7e05452SSean Christopherson If unsure, say N. 1940e7e05452SSean Christopherson 1941506f1d07SSam Ravnborgconfig EFI 19429ba16087SJan Beulich bool "EFI runtime service support" 19435b83683fSHuang, Ying depends on ACPI 1944f6ce5002SSergey Vlasov select UCS2_STRING 1945022ee6c5SArd Biesheuvel select EFI_RUNTIME_WRAPPERS 1946a7f7f624SMasahiro Yamada help 19478b2cb7a8SHuang, Ying This enables the kernel to use EFI runtime services that are 1948506f1d07SSam Ravnborg available (such as the EFI variable services). 1949506f1d07SSam Ravnborg 19508b2cb7a8SHuang, Ying This option is only useful on systems that have EFI firmware. 19518b2cb7a8SHuang, Ying In addition, you should use the latest ELILO loader available 19528b2cb7a8SHuang, Ying at <http://elilo.sourceforge.net> in order to take advantage 19538b2cb7a8SHuang, Ying of EFI runtime services. However, even with this option, the 19548b2cb7a8SHuang, Ying resultant kernel should continue to boot on existing non-EFI 19558b2cb7a8SHuang, Ying platforms. 1956506f1d07SSam Ravnborg 1957291f3632SMatt Flemingconfig EFI_STUB 1958291f3632SMatt Fleming bool "EFI stub support" 1959b16d8c23SMatt Fleming depends on EFI && !X86_USE_3DNOW 19608f24f8c2SArd Biesheuvel depends on $(cc-option,-mabi=ms) || X86_32 19617b2a583aSMatt Fleming select RELOCATABLE 1962a7f7f624SMasahiro Yamada help 1963291f3632SMatt Fleming This kernel feature allows a bzImage to be loaded directly 1964291f3632SMatt Fleming by EFI firmware without the use of a bootloader. 1965291f3632SMatt Fleming 19664f4cfa6cSMauro Carvalho Chehab See Documentation/admin-guide/efi-stub.rst for more information. 19670c759662SMatt Fleming 19687d453eeeSMatt Flemingconfig EFI_MIXED 19697d453eeeSMatt Fleming bool "EFI mixed-mode support" 19707d453eeeSMatt Fleming depends on EFI_STUB && X86_64 1971a7f7f624SMasahiro Yamada help 19727d453eeeSMatt Fleming Enabling this feature allows a 64-bit kernel to be booted 19737d453eeeSMatt Fleming on a 32-bit firmware, provided that your CPU supports 64-bit 19747d453eeeSMatt Fleming mode. 19757d453eeeSMatt Fleming 19767d453eeeSMatt Fleming Note that it is not possible to boot a mixed-mode enabled 19777d453eeeSMatt Fleming kernel via the EFI boot stub - a bootloader that supports 19787d453eeeSMatt Fleming the EFI handover protocol must be used. 19797d453eeeSMatt Fleming 19807d453eeeSMatt Fleming If unsure, say N. 19817d453eeeSMatt Fleming 19828636a1f9SMasahiro Yamadasource "kernel/Kconfig.hz" 1983506f1d07SSam Ravnborg 1984506f1d07SSam Ravnborgconfig KEXEC 1985506f1d07SSam Ravnborg bool "kexec system call" 19862965faa5SDave Young select KEXEC_CORE 1987a7f7f624SMasahiro Yamada help 1988506f1d07SSam Ravnborg kexec is a system call that implements the ability to shutdown your 1989506f1d07SSam Ravnborg current kernel, and to start another kernel. It is like a reboot 1990506f1d07SSam Ravnborg but it is independent of the system firmware. And like a reboot 1991506f1d07SSam Ravnborg you can start any kernel with it, not just Linux. 1992506f1d07SSam Ravnborg 1993506f1d07SSam Ravnborg The name comes from the similarity to the exec system call. 1994506f1d07SSam Ravnborg 1995506f1d07SSam Ravnborg It is an ongoing process to be certain the hardware in a machine 1996506f1d07SSam Ravnborg is properly shutdown, so do not be surprised if this code does not 1997bf220695SGeert Uytterhoeven initially work for you. As of this writing the exact hardware 1998bf220695SGeert Uytterhoeven interface is strongly in flux, so no good recommendation can be 1999bf220695SGeert Uytterhoeven made. 2000506f1d07SSam Ravnborg 200174ca317cSVivek Goyalconfig KEXEC_FILE 200274ca317cSVivek Goyal bool "kexec file based system call" 20032965faa5SDave Young select KEXEC_CORE 200474ca317cSVivek Goyal select BUILD_BIN2C 200574ca317cSVivek Goyal depends on X86_64 200674ca317cSVivek Goyal depends on CRYPTO=y 200774ca317cSVivek Goyal depends on CRYPTO_SHA256=y 2008a7f7f624SMasahiro Yamada help 200974ca317cSVivek Goyal This is new version of kexec system call. This system call is 201074ca317cSVivek Goyal file based and takes file descriptors as system call argument 201174ca317cSVivek Goyal for kernel and initramfs as opposed to list of segments as 201274ca317cSVivek Goyal accepted by previous system call. 201374ca317cSVivek Goyal 2014b799a09fSAKASHI Takahiroconfig ARCH_HAS_KEXEC_PURGATORY 2015b799a09fSAKASHI Takahiro def_bool KEXEC_FILE 2016b799a09fSAKASHI Takahiro 201799d5cadfSJiri Bohacconfig KEXEC_SIG 20188e7d8381SVivek Goyal bool "Verify kernel signature during kexec_file_load() syscall" 201974ca317cSVivek Goyal depends on KEXEC_FILE 2020a7f7f624SMasahiro Yamada help 202199d5cadfSJiri Bohac 202299d5cadfSJiri Bohac This option makes the kexec_file_load() syscall check for a valid 202399d5cadfSJiri Bohac signature of the kernel image. The image can still be loaded without 202499d5cadfSJiri Bohac a valid signature unless you also enable KEXEC_SIG_FORCE, though if 202599d5cadfSJiri Bohac there's a signature that we can check, then it must be valid. 202699d5cadfSJiri Bohac 202799d5cadfSJiri Bohac In addition to this option, you need to enable signature 202899d5cadfSJiri Bohac verification for the corresponding kernel image type being 202999d5cadfSJiri Bohac loaded in order for this to work. 203099d5cadfSJiri Bohac 203199d5cadfSJiri Bohacconfig KEXEC_SIG_FORCE 203299d5cadfSJiri Bohac bool "Require a valid signature in kexec_file_load() syscall" 203399d5cadfSJiri Bohac depends on KEXEC_SIG 2034a7f7f624SMasahiro Yamada help 20358e7d8381SVivek Goyal This option makes kernel signature verification mandatory for 2036d8eb8940SBorislav Petkov the kexec_file_load() syscall. 20378e7d8381SVivek Goyal 20388e7d8381SVivek Goyalconfig KEXEC_BZIMAGE_VERIFY_SIG 20398e7d8381SVivek Goyal bool "Enable bzImage signature verification support" 204099d5cadfSJiri Bohac depends on KEXEC_SIG 20418e7d8381SVivek Goyal depends on SIGNED_PE_FILE_VERIFICATION 20428e7d8381SVivek Goyal select SYSTEM_TRUSTED_KEYRING 2043a7f7f624SMasahiro Yamada help 20448e7d8381SVivek Goyal Enable bzImage signature verification support. 20458e7d8381SVivek Goyal 2046506f1d07SSam Ravnborgconfig CRASH_DUMP 204704b69447SPavel Machek bool "kernel crash dumps" 2048506f1d07SSam Ravnborg depends on X86_64 || (X86_32 && HIGHMEM) 2049a7f7f624SMasahiro Yamada help 2050506f1d07SSam Ravnborg Generate crash dump after being started by kexec. 2051506f1d07SSam Ravnborg This should be normally only set in special crash dump kernels 2052506f1d07SSam Ravnborg which are loaded in the main kernel with kexec-tools into 2053506f1d07SSam Ravnborg a specially reserved region and then later executed after 2054506f1d07SSam Ravnborg a crash by kdump/kexec. The crash dump kernel must be compiled 2055506f1d07SSam Ravnborg to a memory address not used by the main kernel or BIOS using 2056506f1d07SSam Ravnborg PHYSICAL_START, or it must be built as a relocatable image 2057506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y). 2058330d4810SMauro Carvalho Chehab For more details see Documentation/admin-guide/kdump/kdump.rst 2059506f1d07SSam Ravnborg 20603ab83521SHuang Yingconfig KEXEC_JUMP 20616ea30386SKees Cook bool "kexec jump" 2062fee7b0d8SHuang Ying depends on KEXEC && HIBERNATION 2063a7f7f624SMasahiro Yamada help 206489081d17SHuang Ying Jump between original kernel and kexeced kernel and invoke 206589081d17SHuang Ying code in physical address mode via KEXEC 20663ab83521SHuang Ying 2067506f1d07SSam Ravnborgconfig PHYSICAL_START 20686a108a14SDavid Rientjes hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2069ceefccc9SH. Peter Anvin default "0x1000000" 2070a7f7f624SMasahiro Yamada help 2071506f1d07SSam Ravnborg This gives the physical address where the kernel is loaded. 2072506f1d07SSam Ravnborg 2073506f1d07SSam Ravnborg If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2074506f1d07SSam Ravnborg bzImage will decompress itself to above physical address and 2075506f1d07SSam Ravnborg run from there. Otherwise, bzImage will run from the address where 2076506f1d07SSam Ravnborg it has been loaded by the boot loader and will ignore above physical 2077506f1d07SSam Ravnborg address. 2078506f1d07SSam Ravnborg 2079506f1d07SSam Ravnborg In normal kdump cases one does not have to set/change this option 2080506f1d07SSam Ravnborg as now bzImage can be compiled as a completely relocatable image 2081506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2082506f1d07SSam Ravnborg address. This option is mainly useful for the folks who don't want 2083506f1d07SSam Ravnborg to use a bzImage for capturing the crash dump and want to use a 2084506f1d07SSam Ravnborg vmlinux instead. vmlinux is not relocatable hence a kernel needs 2085506f1d07SSam Ravnborg to be specifically compiled to run from a specific memory area 2086506f1d07SSam Ravnborg (normally a reserved region) and this option comes handy. 2087506f1d07SSam Ravnborg 2088ceefccc9SH. Peter Anvin So if you are using bzImage for capturing the crash dump, 2089ceefccc9SH. Peter Anvin leave the value here unchanged to 0x1000000 and set 2090ceefccc9SH. Peter Anvin CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2091ceefccc9SH. Peter Anvin for capturing the crash dump change this value to start of 2092ceefccc9SH. Peter Anvin the reserved region. In other words, it can be set based on 2093ceefccc9SH. Peter Anvin the "X" value as specified in the "crashkernel=YM@XM" 2094ceefccc9SH. Peter Anvin command line boot parameter passed to the panic-ed 2095330d4810SMauro Carvalho Chehab kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2096ceefccc9SH. Peter Anvin for more details about crash dumps. 2097506f1d07SSam Ravnborg 2098506f1d07SSam Ravnborg Usage of bzImage for capturing the crash dump is recommended as 2099506f1d07SSam Ravnborg one does not have to build two kernels. Same kernel can be used 2100506f1d07SSam Ravnborg as production kernel and capture kernel. Above option should have 2101506f1d07SSam Ravnborg gone away after relocatable bzImage support is introduced. But it 2102506f1d07SSam Ravnborg is present because there are users out there who continue to use 2103506f1d07SSam Ravnborg vmlinux for dump capture. This option should go away down the 2104506f1d07SSam Ravnborg line. 2105506f1d07SSam Ravnborg 2106506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2107506f1d07SSam Ravnborg 2108506f1d07SSam Ravnborgconfig RELOCATABLE 210926717808SH. Peter Anvin bool "Build a relocatable kernel" 211026717808SH. Peter Anvin default y 2111a7f7f624SMasahiro Yamada help 2112506f1d07SSam Ravnborg This builds a kernel image that retains relocation information 2113506f1d07SSam Ravnborg so it can be loaded someplace besides the default 1MB. 2114506f1d07SSam Ravnborg The relocations tend to make the kernel binary about 10% larger, 2115506f1d07SSam Ravnborg but are discarded at runtime. 2116506f1d07SSam Ravnborg 2117506f1d07SSam Ravnborg One use is for the kexec on panic case where the recovery kernel 2118506f1d07SSam Ravnborg must live at a different physical address than the primary 2119506f1d07SSam Ravnborg kernel. 2120506f1d07SSam Ravnborg 2121506f1d07SSam Ravnborg Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2122506f1d07SSam Ravnborg it has been loaded at and the compile time physical address 21238ab3820fSKees Cook (CONFIG_PHYSICAL_START) is used as the minimum location. 2124506f1d07SSam Ravnborg 21258ab3820fSKees Cookconfig RANDOMIZE_BASE 2126e8581e3dSBaoquan He bool "Randomize the address of the kernel image (KASLR)" 21278ab3820fSKees Cook depends on RELOCATABLE 21286807c846SIngo Molnar default y 2129a7f7f624SMasahiro Yamada help 2130e8581e3dSBaoquan He In support of Kernel Address Space Layout Randomization (KASLR), 2131e8581e3dSBaoquan He this randomizes the physical address at which the kernel image 2132e8581e3dSBaoquan He is decompressed and the virtual address where the kernel 2133e8581e3dSBaoquan He image is mapped, as a security feature that deters exploit 2134e8581e3dSBaoquan He attempts relying on knowledge of the location of kernel 2135e8581e3dSBaoquan He code internals. 2136e8581e3dSBaoquan He 2137ed9f007eSKees Cook On 64-bit, the kernel physical and virtual addresses are 2138ed9f007eSKees Cook randomized separately. The physical address will be anywhere 2139ed9f007eSKees Cook between 16MB and the top of physical memory (up to 64TB). The 2140ed9f007eSKees Cook virtual address will be randomized from 16MB up to 1GB (9 bits 2141ed9f007eSKees Cook of entropy). Note that this also reduces the memory space 2142ed9f007eSKees Cook available to kernel modules from 1.5GB to 1GB. 2143ed9f007eSKees Cook 2144ed9f007eSKees Cook On 32-bit, the kernel physical and virtual addresses are 2145ed9f007eSKees Cook randomized together. They will be randomized from 16MB up to 2146ed9f007eSKees Cook 512MB (8 bits of entropy). 21478ab3820fSKees Cook 2148a653f356SKees Cook Entropy is generated using the RDRAND instruction if it is 2149e8581e3dSBaoquan He supported. If RDTSC is supported, its value is mixed into 2150e8581e3dSBaoquan He the entropy pool as well. If neither RDRAND nor RDTSC are 2151ed9f007eSKees Cook supported, then entropy is read from the i8254 timer. The 2152ed9f007eSKees Cook usable entropy is limited by the kernel being built using 2153ed9f007eSKees Cook 2GB addressing, and that PHYSICAL_ALIGN must be at a 2154ed9f007eSKees Cook minimum of 2MB. As a result, only 10 bits of entropy are 2155ed9f007eSKees Cook theoretically possible, but the implementations are further 2156ed9f007eSKees Cook limited due to memory layouts. 2157e8581e3dSBaoquan He 21586807c846SIngo Molnar If unsure, say Y. 2159da2b6fb9SKees Cook 21608ab3820fSKees Cook# Relocation on x86 needs some additional build support 2161845adf72SH. Peter Anvinconfig X86_NEED_RELOCS 2162845adf72SH. Peter Anvin def_bool y 21638ab3820fSKees Cook depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2164845adf72SH. Peter Anvin 2165506f1d07SSam Ravnborgconfig PHYSICAL_ALIGN 2166a0215061SKees Cook hex "Alignment value to which kernel should be aligned" 21678ab3820fSKees Cook default "0x200000" 2168a0215061SKees Cook range 0x2000 0x1000000 if X86_32 2169a0215061SKees Cook range 0x200000 0x1000000 if X86_64 2170a7f7f624SMasahiro Yamada help 2171506f1d07SSam Ravnborg This value puts the alignment restrictions on physical address 2172506f1d07SSam Ravnborg where kernel is loaded and run from. Kernel is compiled for an 2173506f1d07SSam Ravnborg address which meets above alignment restriction. 2174506f1d07SSam Ravnborg 2175506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2176506f1d07SSam Ravnborg CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2177506f1d07SSam Ravnborg address aligned to above value and run from there. 2178506f1d07SSam Ravnborg 2179506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2180506f1d07SSam Ravnborg CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2181506f1d07SSam Ravnborg load address and decompress itself to the address it has been 2182506f1d07SSam Ravnborg compiled for and run from there. The address for which kernel is 2183506f1d07SSam Ravnborg compiled already meets above alignment restrictions. Hence the 2184506f1d07SSam Ravnborg end result is that kernel runs from a physical address meeting 2185506f1d07SSam Ravnborg above alignment restrictions. 2186506f1d07SSam Ravnborg 2187a0215061SKees Cook On 32-bit this value must be a multiple of 0x2000. On 64-bit 2188a0215061SKees Cook this value must be a multiple of 0x200000. 2189a0215061SKees Cook 2190506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2191506f1d07SSam Ravnborg 2192eedb92abSKirill A. Shutemovconfig DYNAMIC_MEMORY_LAYOUT 2193eedb92abSKirill A. Shutemov bool 2194a7f7f624SMasahiro Yamada help 2195eedb92abSKirill A. Shutemov This option makes base addresses of vmalloc and vmemmap as well as 2196eedb92abSKirill A. Shutemov __PAGE_OFFSET movable during boot. 2197eedb92abSKirill A. Shutemov 21980483e1faSThomas Garnierconfig RANDOMIZE_MEMORY 21990483e1faSThomas Garnier bool "Randomize the kernel memory sections" 22000483e1faSThomas Garnier depends on X86_64 22010483e1faSThomas Garnier depends on RANDOMIZE_BASE 2202eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 22030483e1faSThomas Garnier default RANDOMIZE_BASE 2204a7f7f624SMasahiro Yamada help 22050483e1faSThomas Garnier Randomizes the base virtual address of kernel memory sections 22060483e1faSThomas Garnier (physical memory mapping, vmalloc & vmemmap). This security feature 22070483e1faSThomas Garnier makes exploits relying on predictable memory locations less reliable. 22080483e1faSThomas Garnier 22090483e1faSThomas Garnier The order of allocations remains unchanged. Entropy is generated in 22100483e1faSThomas Garnier the same way as RANDOMIZE_BASE. Current implementation in the optimal 22110483e1faSThomas Garnier configuration have in average 30,000 different possible virtual 22120483e1faSThomas Garnier addresses for each memory section. 22130483e1faSThomas Garnier 22146807c846SIngo Molnar If unsure, say Y. 22150483e1faSThomas Garnier 221690397a41SThomas Garnierconfig RANDOMIZE_MEMORY_PHYSICAL_PADDING 221790397a41SThomas Garnier hex "Physical memory mapping padding" if EXPERT 221890397a41SThomas Garnier depends on RANDOMIZE_MEMORY 221990397a41SThomas Garnier default "0xa" if MEMORY_HOTPLUG 222090397a41SThomas Garnier default "0x0" 222190397a41SThomas Garnier range 0x1 0x40 if MEMORY_HOTPLUG 222290397a41SThomas Garnier range 0x0 0x40 2223a7f7f624SMasahiro Yamada help 222490397a41SThomas Garnier Define the padding in terabytes added to the existing physical 222590397a41SThomas Garnier memory size during kernel memory randomization. It is useful 222690397a41SThomas Garnier for memory hotplug support but reduces the entropy available for 222790397a41SThomas Garnier address randomization. 222890397a41SThomas Garnier 222990397a41SThomas Garnier If unsure, leave at the default value. 223090397a41SThomas Garnier 2231506f1d07SSam Ravnborgconfig HOTPLUG_CPU 2232bebd024eSThomas Gleixner def_bool y 223340b31360SStephen Rothwell depends on SMP 2234506f1d07SSam Ravnborg 223580aa1dffSFenghua Yuconfig BOOTPARAM_HOTPLUG_CPU0 223680aa1dffSFenghua Yu bool "Set default setting of cpu0_hotpluggable" 22372c922cd0SKees Cook depends on HOTPLUG_CPU 2238a7f7f624SMasahiro Yamada help 223980aa1dffSFenghua Yu Set whether default state of cpu0_hotpluggable is on or off. 224080aa1dffSFenghua Yu 224180aa1dffSFenghua Yu Say Y here to enable CPU0 hotplug by default. If this switch 224280aa1dffSFenghua Yu is turned on, there is no need to give cpu0_hotplug kernel 224380aa1dffSFenghua Yu parameter and the CPU0 hotplug feature is enabled by default. 224480aa1dffSFenghua Yu 224580aa1dffSFenghua Yu Please note: there are two known CPU0 dependencies if you want 224680aa1dffSFenghua Yu to enable the CPU0 hotplug feature either by this switch or by 224780aa1dffSFenghua Yu cpu0_hotplug kernel parameter. 224880aa1dffSFenghua Yu 224980aa1dffSFenghua Yu First, resume from hibernate or suspend always starts from CPU0. 225080aa1dffSFenghua Yu So hibernate and suspend are prevented if CPU0 is offline. 225180aa1dffSFenghua Yu 225280aa1dffSFenghua Yu Second dependency is PIC interrupts always go to CPU0. CPU0 can not 225380aa1dffSFenghua Yu offline if any interrupt can not migrate out of CPU0. There may 225480aa1dffSFenghua Yu be other CPU0 dependencies. 225580aa1dffSFenghua Yu 225680aa1dffSFenghua Yu Please make sure the dependencies are under your control before 225780aa1dffSFenghua Yu you enable this feature. 225880aa1dffSFenghua Yu 225980aa1dffSFenghua Yu Say N if you don't want to enable CPU0 hotplug feature by default. 226080aa1dffSFenghua Yu You still can enable the CPU0 hotplug feature at boot by kernel 226180aa1dffSFenghua Yu parameter cpu0_hotplug. 226280aa1dffSFenghua Yu 2263a71c8bc5SFenghua Yuconfig DEBUG_HOTPLUG_CPU0 2264a71c8bc5SFenghua Yu def_bool n 2265a71c8bc5SFenghua Yu prompt "Debug CPU0 hotplug" 22662c922cd0SKees Cook depends on HOTPLUG_CPU 2267a7f7f624SMasahiro Yamada help 2268a71c8bc5SFenghua Yu Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2269a71c8bc5SFenghua Yu soon as possible and boots up userspace with CPU0 offlined. User 2270a71c8bc5SFenghua Yu can online CPU0 back after boot time. 2271a71c8bc5SFenghua Yu 2272a71c8bc5SFenghua Yu To debug CPU0 hotplug, you need to enable CPU0 offline/online 2273a71c8bc5SFenghua Yu feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2274a71c8bc5SFenghua Yu compilation or giving cpu0_hotplug kernel parameter at boot. 2275a71c8bc5SFenghua Yu 2276a71c8bc5SFenghua Yu If unsure, say N. 2277a71c8bc5SFenghua Yu 2278506f1d07SSam Ravnborgconfig COMPAT_VDSO 2279b0b49f26SAndy Lutomirski def_bool n 2280b0b49f26SAndy Lutomirski prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2281953fee1dSIngo Molnar depends on COMPAT_32 2282a7f7f624SMasahiro Yamada help 2283b0b49f26SAndy Lutomirski Certain buggy versions of glibc will crash if they are 2284b0b49f26SAndy Lutomirski presented with a 32-bit vDSO that is not mapped at the address 2285b0b49f26SAndy Lutomirski indicated in its segment table. 2286e84446deSRandy Dunlap 2287b0b49f26SAndy Lutomirski The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2288b0b49f26SAndy Lutomirski and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2289b0b49f26SAndy Lutomirski 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2290b0b49f26SAndy Lutomirski the only released version with the bug, but OpenSUSE 9 2291b0b49f26SAndy Lutomirski contains a buggy "glibc 2.3.2". 2292506f1d07SSam Ravnborg 2293b0b49f26SAndy Lutomirski The symptom of the bug is that everything crashes on startup, saying: 2294b0b49f26SAndy Lutomirski dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2295b0b49f26SAndy Lutomirski 2296b0b49f26SAndy Lutomirski Saying Y here changes the default value of the vdso32 boot 2297b0b49f26SAndy Lutomirski option from 1 to 0, which turns off the 32-bit vDSO entirely. 2298b0b49f26SAndy Lutomirski This works around the glibc bug but hurts performance. 2299b0b49f26SAndy Lutomirski 2300b0b49f26SAndy Lutomirski If unsure, say N: if you are compiling your own kernel, you 2301b0b49f26SAndy Lutomirski are unlikely to be using a buggy version of glibc. 2302506f1d07SSam Ravnborg 23033dc33bd3SKees Cookchoice 23043dc33bd3SKees Cook prompt "vsyscall table for legacy applications" 23053dc33bd3SKees Cook depends on X86_64 2306625b7b7fSAndy Lutomirski default LEGACY_VSYSCALL_XONLY 23073dc33bd3SKees Cook help 23083dc33bd3SKees Cook Legacy user code that does not know how to find the vDSO expects 23093dc33bd3SKees Cook to be able to issue three syscalls by calling fixed addresses in 23103dc33bd3SKees Cook kernel space. Since this location is not randomized with ASLR, 23113dc33bd3SKees Cook it can be used to assist security vulnerability exploitation. 23123dc33bd3SKees Cook 23133dc33bd3SKees Cook This setting can be changed at boot time via the kernel command 2314bd49e16eSAndy Lutomirski line parameter vsyscall=[emulate|xonly|none]. 23153dc33bd3SKees Cook 23163dc33bd3SKees Cook On a system with recent enough glibc (2.14 or newer) and no 23173dc33bd3SKees Cook static binaries, you can say None without a performance penalty 23183dc33bd3SKees Cook to improve security. 23193dc33bd3SKees Cook 2320bd49e16eSAndy Lutomirski If unsure, select "Emulate execution only". 23213dc33bd3SKees Cook 23223dc33bd3SKees Cook config LEGACY_VSYSCALL_EMULATE 2323bd49e16eSAndy Lutomirski bool "Full emulation" 23243dc33bd3SKees Cook help 2325bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2326bd49e16eSAndy Lutomirski address mapping. This makes the mapping non-executable, but 2327bd49e16eSAndy Lutomirski it still contains readable known contents, which could be 2328bd49e16eSAndy Lutomirski used in certain rare security vulnerability exploits. This 2329bd49e16eSAndy Lutomirski configuration is recommended when using legacy userspace 2330bd49e16eSAndy Lutomirski that still uses vsyscalls along with legacy binary 2331bd49e16eSAndy Lutomirski instrumentation tools that require code to be readable. 2332bd49e16eSAndy Lutomirski 2333bd49e16eSAndy Lutomirski An example of this type of legacy userspace is running 2334bd49e16eSAndy Lutomirski Pin on an old binary that still uses vsyscalls. 2335bd49e16eSAndy Lutomirski 2336bd49e16eSAndy Lutomirski config LEGACY_VSYSCALL_XONLY 2337bd49e16eSAndy Lutomirski bool "Emulate execution only" 2338bd49e16eSAndy Lutomirski help 2339bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2340bd49e16eSAndy Lutomirski address mapping and does not allow reads. This 2341bd49e16eSAndy Lutomirski configuration is recommended when userspace might use the 2342bd49e16eSAndy Lutomirski legacy vsyscall area but support for legacy binary 2343bd49e16eSAndy Lutomirski instrumentation of legacy code is not needed. It mitigates 2344bd49e16eSAndy Lutomirski certain uses of the vsyscall area as an ASLR-bypassing 2345bd49e16eSAndy Lutomirski buffer. 23463dc33bd3SKees Cook 23473dc33bd3SKees Cook config LEGACY_VSYSCALL_NONE 23483dc33bd3SKees Cook bool "None" 23493dc33bd3SKees Cook help 23503dc33bd3SKees Cook There will be no vsyscall mapping at all. This will 23513dc33bd3SKees Cook eliminate any risk of ASLR bypass due to the vsyscall 23523dc33bd3SKees Cook fixed address mapping. Attempts to use the vsyscalls 23533dc33bd3SKees Cook will be reported to dmesg, so that either old or 23543dc33bd3SKees Cook malicious userspace programs can be identified. 23553dc33bd3SKees Cook 23563dc33bd3SKees Cookendchoice 23573dc33bd3SKees Cook 2358516cbf37STim Birdconfig CMDLINE_BOOL 2359516cbf37STim Bird bool "Built-in kernel command line" 2360a7f7f624SMasahiro Yamada help 2361516cbf37STim Bird Allow for specifying boot arguments to the kernel at 2362516cbf37STim Bird build time. On some systems (e.g. embedded ones), it is 2363516cbf37STim Bird necessary or convenient to provide some or all of the 2364516cbf37STim Bird kernel boot arguments with the kernel itself (that is, 2365516cbf37STim Bird to not rely on the boot loader to provide them.) 2366516cbf37STim Bird 2367516cbf37STim Bird To compile command line arguments into the kernel, 2368516cbf37STim Bird set this option to 'Y', then fill in the 236969711ca1SSébastien Hinderer boot arguments in CONFIG_CMDLINE. 2370516cbf37STim Bird 2371516cbf37STim Bird Systems with fully functional boot loaders (i.e. non-embedded) 2372516cbf37STim Bird should leave this option set to 'N'. 2373516cbf37STim Bird 2374516cbf37STim Birdconfig CMDLINE 2375516cbf37STim Bird string "Built-in kernel command string" 2376516cbf37STim Bird depends on CMDLINE_BOOL 2377516cbf37STim Bird default "" 2378a7f7f624SMasahiro Yamada help 2379516cbf37STim Bird Enter arguments here that should be compiled into the kernel 2380516cbf37STim Bird image and used at boot time. If the boot loader provides a 2381516cbf37STim Bird command line at boot time, it is appended to this string to 2382516cbf37STim Bird form the full kernel command line, when the system boots. 2383516cbf37STim Bird 2384516cbf37STim Bird However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2385516cbf37STim Bird change this behavior. 2386516cbf37STim Bird 2387516cbf37STim Bird In most cases, the command line (whether built-in or provided 2388516cbf37STim Bird by the boot loader) should specify the device for the root 2389516cbf37STim Bird file system. 2390516cbf37STim Bird 2391516cbf37STim Birdconfig CMDLINE_OVERRIDE 2392516cbf37STim Bird bool "Built-in command line overrides boot loader arguments" 2393645e6466SAnders Roxell depends on CMDLINE_BOOL && CMDLINE != "" 2394a7f7f624SMasahiro Yamada help 2395516cbf37STim Bird Set this option to 'Y' to have the kernel ignore the boot loader 2396516cbf37STim Bird command line, and use ONLY the built-in command line. 2397516cbf37STim Bird 2398516cbf37STim Bird This is used to work around broken boot loaders. This should 2399516cbf37STim Bird be set to 'N' under normal conditions. 2400516cbf37STim Bird 2401a5b9e5a2SAndy Lutomirskiconfig MODIFY_LDT_SYSCALL 2402a5b9e5a2SAndy Lutomirski bool "Enable the LDT (local descriptor table)" if EXPERT 2403a5b9e5a2SAndy Lutomirski default y 2404a7f7f624SMasahiro Yamada help 2405a5b9e5a2SAndy Lutomirski Linux can allow user programs to install a per-process x86 2406a5b9e5a2SAndy Lutomirski Local Descriptor Table (LDT) using the modify_ldt(2) system 2407a5b9e5a2SAndy Lutomirski call. This is required to run 16-bit or segmented code such as 2408a5b9e5a2SAndy Lutomirski DOSEMU or some Wine programs. It is also used by some very old 2409a5b9e5a2SAndy Lutomirski threading libraries. 2410a5b9e5a2SAndy Lutomirski 2411a5b9e5a2SAndy Lutomirski Enabling this feature adds a small amount of overhead to 2412a5b9e5a2SAndy Lutomirski context switches and increases the low-level kernel attack 2413a5b9e5a2SAndy Lutomirski surface. Disabling it removes the modify_ldt(2) system call. 2414a5b9e5a2SAndy Lutomirski 2415a5b9e5a2SAndy Lutomirski Saying 'N' here may make sense for embedded or server kernels. 2416a5b9e5a2SAndy Lutomirski 2417b700e7f0SSeth Jenningssource "kernel/livepatch/Kconfig" 2418b700e7f0SSeth Jennings 2419506f1d07SSam Ravnborgendmenu 2420506f1d07SSam Ravnborg 24213072e413SMichal Hockoconfig ARCH_HAS_ADD_PAGES 24223072e413SMichal Hocko def_bool y 24233072e413SMichal Hocko depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 24243072e413SMichal Hocko 2425506f1d07SSam Ravnborgconfig ARCH_ENABLE_MEMORY_HOTPLUG 2426506f1d07SSam Ravnborg def_bool y 2427506f1d07SSam Ravnborg depends on X86_64 || (X86_32 && HIGHMEM) 2428506f1d07SSam Ravnborg 242935551053SGary Hadeconfig ARCH_ENABLE_MEMORY_HOTREMOVE 243035551053SGary Hade def_bool y 243135551053SGary Hade depends on MEMORY_HOTPLUG 243235551053SGary Hade 2433e534c7c5SLee Schermerhornconfig USE_PERCPU_NUMA_NODE_ID 2434645a7919STejun Heo def_bool y 2435e534c7c5SLee Schermerhorn depends on NUMA 2436e534c7c5SLee Schermerhorn 24379491846fSKirill A. Shutemovconfig ARCH_ENABLE_SPLIT_PMD_PTLOCK 24389491846fSKirill A. Shutemov def_bool y 24399491846fSKirill A. Shutemov depends on X86_64 || X86_PAE 24409491846fSKirill A. Shutemov 2441c177c81eSNaoya Horiguchiconfig ARCH_ENABLE_HUGEPAGE_MIGRATION 2442c177c81eSNaoya Horiguchi def_bool y 2443c177c81eSNaoya Horiguchi depends on X86_64 && HUGETLB_PAGE && MIGRATION 2444c177c81eSNaoya Horiguchi 24459c670ea3SNaoya Horiguchiconfig ARCH_ENABLE_THP_MIGRATION 24469c670ea3SNaoya Horiguchi def_bool y 24479c670ea3SNaoya Horiguchi depends on X86_64 && TRANSPARENT_HUGEPAGE 24489c670ea3SNaoya Horiguchi 2449da85f865SBjorn Helgaasmenu "Power management and ACPI options" 2450e279b6c1SSam Ravnborg 2451e279b6c1SSam Ravnborgconfig ARCH_HIBERNATION_HEADER 24523c2362e6SHarvey Harrison def_bool y 245344556530SZhimin Gu depends on HIBERNATION 2454e279b6c1SSam Ravnborg 2455e279b6c1SSam Ravnborgsource "kernel/power/Kconfig" 2456e279b6c1SSam Ravnborg 2457e279b6c1SSam Ravnborgsource "drivers/acpi/Kconfig" 2458e279b6c1SSam Ravnborg 2459a6b68076SAndi Kleenconfig X86_APM_BOOT 24606fc108a0SJan Beulich def_bool y 2461282e5aabSPaul Bolle depends on APM 2462a6b68076SAndi Kleen 2463e279b6c1SSam Ravnborgmenuconfig APM 2464e279b6c1SSam Ravnborg tristate "APM (Advanced Power Management) BIOS support" 2465efefa6f6SIngo Molnar depends on X86_32 && PM_SLEEP 2466a7f7f624SMasahiro Yamada help 2467e279b6c1SSam Ravnborg APM is a BIOS specification for saving power using several different 2468e279b6c1SSam Ravnborg techniques. This is mostly useful for battery powered laptops with 2469e279b6c1SSam Ravnborg APM compliant BIOSes. If you say Y here, the system time will be 2470e279b6c1SSam Ravnborg reset after a RESUME operation, the /proc/apm device will provide 2471e279b6c1SSam Ravnborg battery status information, and user-space programs will receive 2472e279b6c1SSam Ravnborg notification of APM "events" (e.g. battery status change). 2473e279b6c1SSam Ravnborg 2474e279b6c1SSam Ravnborg If you select "Y" here, you can disable actual use of the APM 2475e279b6c1SSam Ravnborg BIOS by passing the "apm=off" option to the kernel at boot time. 2476e279b6c1SSam Ravnborg 2477e279b6c1SSam Ravnborg Note that the APM support is almost completely disabled for 2478e279b6c1SSam Ravnborg machines with more than one CPU. 2479e279b6c1SSam Ravnborg 2480e279b6c1SSam Ravnborg In order to use APM, you will need supporting software. For location 2481151f4e2bSMauro Carvalho Chehab and more information, read <file:Documentation/power/apm-acpi.rst> 24822dc98fd3SMichael Witten and the Battery Powered Linux mini-HOWTO, available from 2483e279b6c1SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 2484e279b6c1SSam Ravnborg 2485e279b6c1SSam Ravnborg This driver does not spin down disk drives (see the hdparm(8) 2486e279b6c1SSam Ravnborg manpage ("man 8 hdparm") for that), and it doesn't turn off 2487e279b6c1SSam Ravnborg VESA-compliant "green" monitors. 2488e279b6c1SSam Ravnborg 2489e279b6c1SSam Ravnborg This driver does not support the TI 4000M TravelMate and the ACER 2490e279b6c1SSam Ravnborg 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2491e279b6c1SSam Ravnborg desktop machines also don't have compliant BIOSes, and this driver 2492e279b6c1SSam Ravnborg may cause those machines to panic during the boot phase. 2493e279b6c1SSam Ravnborg 2494e279b6c1SSam Ravnborg Generally, if you don't have a battery in your machine, there isn't 2495e279b6c1SSam Ravnborg much point in using this driver and you should say N. If you get 2496e279b6c1SSam Ravnborg random kernel OOPSes or reboots that don't seem to be related to 2497e279b6c1SSam Ravnborg anything, try disabling/enabling this option (or disabling/enabling 2498e279b6c1SSam Ravnborg APM in your BIOS). 2499e279b6c1SSam Ravnborg 2500e279b6c1SSam Ravnborg Some other things you should try when experiencing seemingly random, 2501e279b6c1SSam Ravnborg "weird" problems: 2502e279b6c1SSam Ravnborg 2503e279b6c1SSam Ravnborg 1) make sure that you have enough swap space and that it is 2504e279b6c1SSam Ravnborg enabled. 2505e279b6c1SSam Ravnborg 2) pass the "no-hlt" option to the kernel 2506e279b6c1SSam Ravnborg 3) switch on floating point emulation in the kernel and pass 2507e279b6c1SSam Ravnborg the "no387" option to the kernel 2508e279b6c1SSam Ravnborg 4) pass the "floppy=nodma" option to the kernel 2509e279b6c1SSam Ravnborg 5) pass the "mem=4M" option to the kernel (thereby disabling 2510e279b6c1SSam Ravnborg all but the first 4 MB of RAM) 2511e279b6c1SSam Ravnborg 6) make sure that the CPU is not over clocked. 2512e279b6c1SSam Ravnborg 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2513e279b6c1SSam Ravnborg 8) disable the cache from your BIOS settings 2514e279b6c1SSam Ravnborg 9) install a fan for the video card or exchange video RAM 2515e279b6c1SSam Ravnborg 10) install a better fan for the CPU 2516e279b6c1SSam Ravnborg 11) exchange RAM chips 2517e279b6c1SSam Ravnborg 12) exchange the motherboard. 2518e279b6c1SSam Ravnborg 2519e279b6c1SSam Ravnborg To compile this driver as a module, choose M here: the 2520e279b6c1SSam Ravnborg module will be called apm. 2521e279b6c1SSam Ravnborg 2522e279b6c1SSam Ravnborgif APM 2523e279b6c1SSam Ravnborg 2524e279b6c1SSam Ravnborgconfig APM_IGNORE_USER_SUSPEND 2525e279b6c1SSam Ravnborg bool "Ignore USER SUSPEND" 2526a7f7f624SMasahiro Yamada help 2527e279b6c1SSam Ravnborg This option will ignore USER SUSPEND requests. On machines with a 2528e279b6c1SSam Ravnborg compliant APM BIOS, you want to say N. However, on the NEC Versa M 2529e279b6c1SSam Ravnborg series notebooks, it is necessary to say Y because of a BIOS bug. 2530e279b6c1SSam Ravnborg 2531e279b6c1SSam Ravnborgconfig APM_DO_ENABLE 2532e279b6c1SSam Ravnborg bool "Enable PM at boot time" 2533a7f7f624SMasahiro Yamada help 2534e279b6c1SSam Ravnborg Enable APM features at boot time. From page 36 of the APM BIOS 2535e279b6c1SSam Ravnborg specification: "When disabled, the APM BIOS does not automatically 2536e279b6c1SSam Ravnborg power manage devices, enter the Standby State, enter the Suspend 2537e279b6c1SSam Ravnborg State, or take power saving steps in response to CPU Idle calls." 2538e279b6c1SSam Ravnborg This driver will make CPU Idle calls when Linux is idle (unless this 2539e279b6c1SSam Ravnborg feature is turned off -- see "Do CPU IDLE calls", below). This 2540e279b6c1SSam Ravnborg should always save battery power, but more complicated APM features 2541e279b6c1SSam Ravnborg will be dependent on your BIOS implementation. You may need to turn 2542e279b6c1SSam Ravnborg this option off if your computer hangs at boot time when using APM 2543e279b6c1SSam Ravnborg support, or if it beeps continuously instead of suspending. Turn 2544e279b6c1SSam Ravnborg this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2545e279b6c1SSam Ravnborg T400CDT. This is off by default since most machines do fine without 2546e279b6c1SSam Ravnborg this feature. 2547e279b6c1SSam Ravnborg 2548e279b6c1SSam Ravnborgconfig APM_CPU_IDLE 2549dd8af076SLen Brown depends on CPU_IDLE 2550e279b6c1SSam Ravnborg bool "Make CPU Idle calls when idle" 2551a7f7f624SMasahiro Yamada help 2552e279b6c1SSam Ravnborg Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2553e279b6c1SSam Ravnborg On some machines, this can activate improved power savings, such as 2554e279b6c1SSam Ravnborg a slowed CPU clock rate, when the machine is idle. These idle calls 2555e279b6c1SSam Ravnborg are made after the idle loop has run for some length of time (e.g., 2556e279b6c1SSam Ravnborg 333 mS). On some machines, this will cause a hang at boot time or 2557e279b6c1SSam Ravnborg whenever the CPU becomes idle. (On machines with more than one CPU, 2558e279b6c1SSam Ravnborg this option does nothing.) 2559e279b6c1SSam Ravnborg 2560e279b6c1SSam Ravnborgconfig APM_DISPLAY_BLANK 2561e279b6c1SSam Ravnborg bool "Enable console blanking using APM" 2562a7f7f624SMasahiro Yamada help 2563e279b6c1SSam Ravnborg Enable console blanking using the APM. Some laptops can use this to 2564e279b6c1SSam Ravnborg turn off the LCD backlight when the screen blanker of the Linux 2565e279b6c1SSam Ravnborg virtual console blanks the screen. Note that this is only used by 2566e279b6c1SSam Ravnborg the virtual console screen blanker, and won't turn off the backlight 2567e279b6c1SSam Ravnborg when using the X Window system. This also doesn't have anything to 2568e279b6c1SSam Ravnborg do with your VESA-compliant power-saving monitor. Further, this 2569e279b6c1SSam Ravnborg option doesn't work for all laptops -- it might not turn off your 2570e279b6c1SSam Ravnborg backlight at all, or it might print a lot of errors to the console, 2571e279b6c1SSam Ravnborg especially if you are using gpm. 2572e279b6c1SSam Ravnborg 2573e279b6c1SSam Ravnborgconfig APM_ALLOW_INTS 2574e279b6c1SSam Ravnborg bool "Allow interrupts during APM BIOS calls" 2575a7f7f624SMasahiro Yamada help 2576e279b6c1SSam Ravnborg Normally we disable external interrupts while we are making calls to 2577e279b6c1SSam Ravnborg the APM BIOS as a measure to lessen the effects of a badly behaving 2578e279b6c1SSam Ravnborg BIOS implementation. The BIOS should reenable interrupts if it 2579e279b6c1SSam Ravnborg needs to. Unfortunately, some BIOSes do not -- especially those in 2580e279b6c1SSam Ravnborg many of the newer IBM Thinkpads. If you experience hangs when you 2581e279b6c1SSam Ravnborg suspend, try setting this to Y. Otherwise, say N. 2582e279b6c1SSam Ravnborg 2583e279b6c1SSam Ravnborgendif # APM 2584e279b6c1SSam Ravnborg 2585bb0a56ecSDave Jonessource "drivers/cpufreq/Kconfig" 2586e279b6c1SSam Ravnborg 2587e279b6c1SSam Ravnborgsource "drivers/cpuidle/Kconfig" 2588e279b6c1SSam Ravnborg 258927471fdbSAndy Henroidsource "drivers/idle/Kconfig" 259027471fdbSAndy Henroid 2591e279b6c1SSam Ravnborgendmenu 2592e279b6c1SSam Ravnborg 2593e279b6c1SSam Ravnborg 2594e279b6c1SSam Ravnborgmenu "Bus options (PCI etc.)" 2595e279b6c1SSam Ravnborg 2596e279b6c1SSam Ravnborgchoice 2597e279b6c1SSam Ravnborg prompt "PCI access mode" 2598efefa6f6SIngo Molnar depends on X86_32 && PCI 2599e279b6c1SSam Ravnborg default PCI_GOANY 2600a7f7f624SMasahiro Yamada help 2601e279b6c1SSam Ravnborg On PCI systems, the BIOS can be used to detect the PCI devices and 2602e279b6c1SSam Ravnborg determine their configuration. However, some old PCI motherboards 2603e279b6c1SSam Ravnborg have BIOS bugs and may crash if this is done. Also, some embedded 2604e279b6c1SSam Ravnborg PCI-based systems don't have any BIOS at all. Linux can also try to 2605e279b6c1SSam Ravnborg detect the PCI hardware directly without using the BIOS. 2606e279b6c1SSam Ravnborg 2607e279b6c1SSam Ravnborg With this option, you can specify how Linux should detect the 2608e279b6c1SSam Ravnborg PCI devices. If you choose "BIOS", the BIOS will be used, 2609e279b6c1SSam Ravnborg if you choose "Direct", the BIOS won't be used, and if you 2610e279b6c1SSam Ravnborg choose "MMConfig", then PCI Express MMCONFIG will be used. 2611e279b6c1SSam Ravnborg If you choose "Any", the kernel will try MMCONFIG, then the 2612e279b6c1SSam Ravnborg direct access method and falls back to the BIOS if that doesn't 2613e279b6c1SSam Ravnborg work. If unsure, go with the default, which is "Any". 2614e279b6c1SSam Ravnborg 2615e279b6c1SSam Ravnborgconfig PCI_GOBIOS 2616e279b6c1SSam Ravnborg bool "BIOS" 2617e279b6c1SSam Ravnborg 2618e279b6c1SSam Ravnborgconfig PCI_GOMMCONFIG 2619e279b6c1SSam Ravnborg bool "MMConfig" 2620e279b6c1SSam Ravnborg 2621e279b6c1SSam Ravnborgconfig PCI_GODIRECT 2622e279b6c1SSam Ravnborg bool "Direct" 2623e279b6c1SSam Ravnborg 26243ef0e1f8SAndres Salomonconfig PCI_GOOLPC 262576fb6570SDaniel Drake bool "OLPC XO-1" 26263ef0e1f8SAndres Salomon depends on OLPC 26273ef0e1f8SAndres Salomon 26282bdd1b03SAndres Salomonconfig PCI_GOANY 26292bdd1b03SAndres Salomon bool "Any" 26302bdd1b03SAndres Salomon 2631e279b6c1SSam Ravnborgendchoice 2632e279b6c1SSam Ravnborg 2633e279b6c1SSam Ravnborgconfig PCI_BIOS 26343c2362e6SHarvey Harrison def_bool y 2635efefa6f6SIngo Molnar depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2636e279b6c1SSam Ravnborg 2637e279b6c1SSam Ravnborg# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2638e279b6c1SSam Ravnborgconfig PCI_DIRECT 26393c2362e6SHarvey Harrison def_bool y 26400aba496fSShaohua Li depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2641e279b6c1SSam Ravnborg 2642e279b6c1SSam Ravnborgconfig PCI_MMCONFIG 2643b45c9f36SJan Kiszka bool "Support mmconfig PCI config space access" if X86_64 2644b45c9f36SJan Kiszka default y 2645*4590d98fSAndy Shevchenko depends on PCI && (ACPI || JAILHOUSE_GUEST) 2646b45c9f36SJan Kiszka depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2647e279b6c1SSam Ravnborg 26483ef0e1f8SAndres Salomonconfig PCI_OLPC 26492bdd1b03SAndres Salomon def_bool y 26502bdd1b03SAndres Salomon depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 26513ef0e1f8SAndres Salomon 2652b5401a96SAlex Nixonconfig PCI_XEN 2653b5401a96SAlex Nixon def_bool y 2654b5401a96SAlex Nixon depends on PCI && XEN 2655b5401a96SAlex Nixon select SWIOTLB_XEN 2656b5401a96SAlex Nixon 26578364e1f8SJan Kiszkaconfig MMCONF_FAM10H 26588364e1f8SJan Kiszka def_bool y 26598364e1f8SJan Kiszka depends on X86_64 && PCI_MMCONFIG && ACPI 2660e279b6c1SSam Ravnborg 26613f6ea84aSIra W. Snyderconfig PCI_CNB20LE_QUIRK 26626a108a14SDavid Rientjes bool "Read CNB20LE Host Bridge Windows" if EXPERT 26636ea30386SKees Cook depends on PCI 26643f6ea84aSIra W. Snyder help 26653f6ea84aSIra W. Snyder Read the PCI windows out of the CNB20LE host bridge. This allows 26663f6ea84aSIra W. Snyder PCI hotplug to work on systems with the CNB20LE chipset which do 26673f6ea84aSIra W. Snyder not have ACPI. 26683f6ea84aSIra W. Snyder 266964a5fed6SBjorn Helgaas There's no public spec for this chipset, and this functionality 267064a5fed6SBjorn Helgaas is known to be incomplete. 267164a5fed6SBjorn Helgaas 267264a5fed6SBjorn Helgaas You should say N unless you know you need this. 267364a5fed6SBjorn Helgaas 26743a495511SWilliam Breathitt Grayconfig ISA_BUS 267517a2a129SWilliam Breathitt Gray bool "ISA bus support on modern systems" if EXPERT 26763a495511SWilliam Breathitt Gray help 267717a2a129SWilliam Breathitt Gray Expose ISA bus device drivers and options available for selection and 267817a2a129SWilliam Breathitt Gray configuration. Enable this option if your target machine has an ISA 267917a2a129SWilliam Breathitt Gray bus. ISA is an older system, displaced by PCI and newer bus 268017a2a129SWilliam Breathitt Gray architectures -- if your target machine is modern, it probably does 268117a2a129SWilliam Breathitt Gray not have an ISA bus. 26823a495511SWilliam Breathitt Gray 26833a495511SWilliam Breathitt Gray If unsure, say N. 26843a495511SWilliam Breathitt Gray 26851c00f016SDavid Rientjes# x86_64 have no ISA slots, but can have ISA-style DMA. 2686e279b6c1SSam Ravnborgconfig ISA_DMA_API 26871c00f016SDavid Rientjes bool "ISA-style DMA support" if (X86_64 && EXPERT) 26881c00f016SDavid Rientjes default y 26891c00f016SDavid Rientjes help 26901c00f016SDavid Rientjes Enables ISA-style DMA support for devices requiring such controllers. 26911c00f016SDavid Rientjes If unsure, say Y. 2692e279b6c1SSam Ravnborg 269351e68d05SLinus Torvaldsif X86_32 269451e68d05SLinus Torvalds 2695e279b6c1SSam Ravnborgconfig ISA 2696e279b6c1SSam Ravnborg bool "ISA support" 2697a7f7f624SMasahiro Yamada help 2698e279b6c1SSam Ravnborg Find out whether you have ISA slots on your motherboard. ISA is the 2699e279b6c1SSam Ravnborg name of a bus system, i.e. the way the CPU talks to the other stuff 2700e279b6c1SSam Ravnborg inside your box. Other bus systems are PCI, EISA, MicroChannel 2701e279b6c1SSam Ravnborg (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2702e279b6c1SSam Ravnborg newer boards don't support it. If you have ISA, say Y, otherwise N. 2703e279b6c1SSam Ravnborg 2704e279b6c1SSam Ravnborgconfig SCx200 2705e279b6c1SSam Ravnborg tristate "NatSemi SCx200 support" 2706a7f7f624SMasahiro Yamada help 2707e279b6c1SSam Ravnborg This provides basic support for National Semiconductor's 2708e279b6c1SSam Ravnborg (now AMD's) Geode processors. The driver probes for the 2709e279b6c1SSam Ravnborg PCI-IDs of several on-chip devices, so its a good dependency 2710e279b6c1SSam Ravnborg for other scx200_* drivers. 2711e279b6c1SSam Ravnborg 2712e279b6c1SSam Ravnborg If compiled as a module, the driver is named scx200. 2713e279b6c1SSam Ravnborg 2714e279b6c1SSam Ravnborgconfig SCx200HR_TIMER 2715e279b6c1SSam Ravnborg tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2716592913ecSJohn Stultz depends on SCx200 2717e279b6c1SSam Ravnborg default y 2718a7f7f624SMasahiro Yamada help 2719e279b6c1SSam Ravnborg This driver provides a clocksource built upon the on-chip 2720e279b6c1SSam Ravnborg 27MHz high-resolution timer. Its also a workaround for 2721e279b6c1SSam Ravnborg NSC Geode SC-1100's buggy TSC, which loses time when the 2722e279b6c1SSam Ravnborg processor goes idle (as is done by the scheduler). The 2723e279b6c1SSam Ravnborg other workaround is idle=poll boot option. 2724e279b6c1SSam Ravnborg 27253ef0e1f8SAndres Salomonconfig OLPC 27263ef0e1f8SAndres Salomon bool "One Laptop Per Child support" 272754008979SThomas Gleixner depends on !X86_PAE 27283c554946SAndres Salomon select GPIOLIB 2729dc3119e7SThomas Gleixner select OF 273045bb1674SDaniel Drake select OF_PROMTREE 2731b4e51854SGrant Likely select IRQ_DOMAIN 27320c3d931bSLubomir Rintel select OLPC_EC 2733a7f7f624SMasahiro Yamada help 27343ef0e1f8SAndres Salomon Add support for detecting the unique features of the OLPC 27353ef0e1f8SAndres Salomon XO hardware. 27363ef0e1f8SAndres Salomon 2737a3128588SDaniel Drakeconfig OLPC_XO1_PM 2738a3128588SDaniel Drake bool "OLPC XO-1 Power Management" 2739fa112cf1SBorislav Petkov depends on OLPC && MFD_CS5535=y && PM_SLEEP 2740a7f7f624SMasahiro Yamada help 274197c4cb71SDaniel Drake Add support for poweroff and suspend of the OLPC XO-1 laptop. 2742bf1ebf00SDaniel Drake 2743cfee9597SDaniel Drakeconfig OLPC_XO1_RTC 2744cfee9597SDaniel Drake bool "OLPC XO-1 Real Time Clock" 2745cfee9597SDaniel Drake depends on OLPC_XO1_PM && RTC_DRV_CMOS 2746a7f7f624SMasahiro Yamada help 2747cfee9597SDaniel Drake Add support for the XO-1 real time clock, which can be used as a 2748cfee9597SDaniel Drake programmable wakeup source. 2749cfee9597SDaniel Drake 27507feda8e9SDaniel Drakeconfig OLPC_XO1_SCI 27517feda8e9SDaniel Drake bool "OLPC XO-1 SCI extras" 275292e830f2SArnd Bergmann depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2753ed8e47feSRandy Dunlap depends on INPUT=y 2754d8d01a63SDaniel Drake select POWER_SUPPLY 2755a7f7f624SMasahiro Yamada help 27567feda8e9SDaniel Drake Add support for SCI-based features of the OLPC XO-1 laptop: 27577bc74b3dSDaniel Drake - EC-driven system wakeups 27587feda8e9SDaniel Drake - Power button 27597bc74b3dSDaniel Drake - Ebook switch 27602cf2baeaSDaniel Drake - Lid switch 2761e1040ac6SDaniel Drake - AC adapter status updates 2762e1040ac6SDaniel Drake - Battery status updates 27637feda8e9SDaniel Drake 2764a0f30f59SDaniel Drakeconfig OLPC_XO15_SCI 2765a0f30f59SDaniel Drake bool "OLPC XO-1.5 SCI extras" 2766d8d01a63SDaniel Drake depends on OLPC && ACPI 2767d8d01a63SDaniel Drake select POWER_SUPPLY 2768a7f7f624SMasahiro Yamada help 2769a0f30f59SDaniel Drake Add support for SCI-based features of the OLPC XO-1.5 laptop: 2770a0f30f59SDaniel Drake - EC-driven system wakeups 2771a0f30f59SDaniel Drake - AC adapter status updates 2772a0f30f59SDaniel Drake - Battery status updates 2773e279b6c1SSam Ravnborg 2774d4f3e350SEd Wildgooseconfig ALIX 2775d4f3e350SEd Wildgoose bool "PCEngines ALIX System Support (LED setup)" 2776d4f3e350SEd Wildgoose select GPIOLIB 2777a7f7f624SMasahiro Yamada help 2778d4f3e350SEd Wildgoose This option enables system support for the PCEngines ALIX. 2779d4f3e350SEd Wildgoose At present this just sets up LEDs for GPIO control on 2780d4f3e350SEd Wildgoose ALIX2/3/6 boards. However, other system specific setup should 2781d4f3e350SEd Wildgoose get added here. 2782d4f3e350SEd Wildgoose 2783d4f3e350SEd Wildgoose Note: You must still enable the drivers for GPIO and LED support 2784d4f3e350SEd Wildgoose (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2785d4f3e350SEd Wildgoose 2786d4f3e350SEd Wildgoose Note: You have to set alix.force=1 for boards with Award BIOS. 2787d4f3e350SEd Wildgoose 2788da4e3302SPhilip Prindevilleconfig NET5501 2789da4e3302SPhilip Prindeville bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2790da4e3302SPhilip Prindeville select GPIOLIB 2791a7f7f624SMasahiro Yamada help 2792da4e3302SPhilip Prindeville This option enables system support for the Soekris Engineering net5501. 2793da4e3302SPhilip Prindeville 27943197059aSPhilip A. Prindevilleconfig GEOS 27953197059aSPhilip A. Prindeville bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 27963197059aSPhilip A. Prindeville select GPIOLIB 27973197059aSPhilip A. Prindeville depends on DMI 2798a7f7f624SMasahiro Yamada help 27993197059aSPhilip A. Prindeville This option enables system support for the Traverse Technologies GEOS. 28003197059aSPhilip A. Prindeville 28017d029125SVivien Didelotconfig TS5500 28027d029125SVivien Didelot bool "Technologic Systems TS-5500 platform support" 28037d029125SVivien Didelot depends on MELAN 28047d029125SVivien Didelot select CHECK_SIGNATURE 28057d029125SVivien Didelot select NEW_LEDS 28067d029125SVivien Didelot select LEDS_CLASS 2807a7f7f624SMasahiro Yamada help 28087d029125SVivien Didelot This option enables system support for the Technologic Systems TS-5500. 28097d029125SVivien Didelot 2810e279b6c1SSam Ravnborgendif # X86_32 2811e279b6c1SSam Ravnborg 281223ac4ae8SAndreas Herrmannconfig AMD_NB 2813e279b6c1SSam Ravnborg def_bool y 28140e152cd7SBorislav Petkov depends on CPU_SUP_AMD && PCI 2815e279b6c1SSam Ravnborg 2816e3263ab3SDavid Herrmannconfig X86_SYSFB 2817e3263ab3SDavid Herrmann bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2818e3263ab3SDavid Herrmann help 2819e3263ab3SDavid Herrmann Firmwares often provide initial graphics framebuffers so the BIOS, 2820e3263ab3SDavid Herrmann bootloader or kernel can show basic video-output during boot for 2821e3263ab3SDavid Herrmann user-guidance and debugging. Historically, x86 used the VESA BIOS 2822e3263ab3SDavid Herrmann Extensions and EFI-framebuffers for this, which are mostly limited 2823e3263ab3SDavid Herrmann to x86. 2824e3263ab3SDavid Herrmann This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2825e3263ab3SDavid Herrmann framebuffers so the new generic system-framebuffer drivers can be 2826e3263ab3SDavid Herrmann used on x86. If the framebuffer is not compatible with the generic 2827e3a5dc08SNikolas Nyby modes, it is advertised as fallback platform framebuffer so legacy 2828e3263ab3SDavid Herrmann drivers like efifb, vesafb and uvesafb can pick it up. 2829e3263ab3SDavid Herrmann If this option is not selected, all system framebuffers are always 2830e3263ab3SDavid Herrmann marked as fallback platform framebuffers as usual. 2831e3263ab3SDavid Herrmann 2832e3263ab3SDavid Herrmann Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2833e3263ab3SDavid Herrmann not be able to pick up generic system framebuffers if this option 2834e3263ab3SDavid Herrmann is selected. You are highly encouraged to enable simplefb as 2835e3263ab3SDavid Herrmann replacement if you select this option. simplefb can correctly deal 2836e3263ab3SDavid Herrmann with generic system framebuffers. But you should still keep vesafb 2837e3263ab3SDavid Herrmann and others enabled as fallback if a system framebuffer is 2838e3263ab3SDavid Herrmann incompatible with simplefb. 2839e3263ab3SDavid Herrmann 2840e3263ab3SDavid Herrmann If unsure, say Y. 2841e3263ab3SDavid Herrmann 2842e279b6c1SSam Ravnborgendmenu 2843e279b6c1SSam Ravnborg 2844e279b6c1SSam Ravnborg 28451572497cSChristoph Hellwigmenu "Binary Emulations" 2846e279b6c1SSam Ravnborg 2847e279b6c1SSam Ravnborgconfig IA32_EMULATION 2848e279b6c1SSam Ravnborg bool "IA32 Emulation" 2849e279b6c1SSam Ravnborg depends on X86_64 285039f88911SIngo Molnar select ARCH_WANT_OLD_COMPAT_IPC 2851d1603990SRandy Dunlap select BINFMT_ELF 2852a97f52e6SRoland McGrath select COMPAT_BINFMT_ELF 285339f88911SIngo Molnar select COMPAT_OLD_SIGACTION 2854a7f7f624SMasahiro Yamada help 28555fd92e65SH. J. Lu Include code to run legacy 32-bit programs under a 28565fd92e65SH. J. Lu 64-bit kernel. You should likely turn this on, unless you're 28575fd92e65SH. J. Lu 100% sure that you don't have any 32-bit programs left. 2858e279b6c1SSam Ravnborg 2859e279b6c1SSam Ravnborgconfig IA32_AOUT 2860e279b6c1SSam Ravnborg tristate "IA32 a.out support" 28616b213e1bSDavid Woodhouse depends on IA32_EMULATION 2862eac61655SBorislav Petkov depends on BROKEN 2863a7f7f624SMasahiro Yamada help 2864e279b6c1SSam Ravnborg Support old a.out binaries in the 32bit emulation. 2865e279b6c1SSam Ravnborg 28660bf62763SH. Peter Anvinconfig X86_X32 28676ea30386SKees Cook bool "x32 ABI for 64-bit mode" 28689b54050bSBrian Gerst depends on X86_64 2869a7f7f624SMasahiro Yamada help 28705fd92e65SH. J. Lu Include code to run binaries for the x32 native 32-bit ABI 28715fd92e65SH. J. Lu for 64-bit processors. An x32 process gets access to the 28725fd92e65SH. J. Lu full 64-bit register file and wide data path while leaving 28735fd92e65SH. J. Lu pointers at 32 bits for smaller memory footprint. 28745fd92e65SH. J. Lu 28755fd92e65SH. J. Lu You will need a recent binutils (2.22 or later) with 28765fd92e65SH. J. Lu elf32_x86_64 support enabled to compile a kernel with this 28775fd92e65SH. J. Lu option set. 28785fd92e65SH. J. Lu 2879953fee1dSIngo Molnarconfig COMPAT_32 2880953fee1dSIngo Molnar def_bool y 2881953fee1dSIngo Molnar depends on IA32_EMULATION || X86_32 2882953fee1dSIngo Molnar select HAVE_UID16 2883953fee1dSIngo Molnar select OLD_SIGSUSPEND3 2884953fee1dSIngo Molnar 2885e279b6c1SSam Ravnborgconfig COMPAT 28863c2362e6SHarvey Harrison def_bool y 28870bf62763SH. Peter Anvin depends on IA32_EMULATION || X86_X32 2888e279b6c1SSam Ravnborg 28893120e25eSJan Beulichif COMPAT 2890e279b6c1SSam Ravnborgconfig COMPAT_FOR_U64_ALIGNMENT 28913120e25eSJan Beulich def_bool y 2892e279b6c1SSam Ravnborg 2893e279b6c1SSam Ravnborgconfig SYSVIPC_COMPAT 28943c2362e6SHarvey Harrison def_bool y 28953120e25eSJan Beulich depends on SYSVIPC 28963120e25eSJan Beulichendif 2897ee009e4aSDavid Howells 2898e279b6c1SSam Ravnborgendmenu 2899e279b6c1SSam Ravnborg 2900e279b6c1SSam Ravnborg 2901e5beae16SKeith Packardconfig HAVE_ATOMIC_IOMAP 2902e5beae16SKeith Packard def_bool y 2903e5beae16SKeith Packard depends on X86_32 2904e5beae16SKeith Packard 2905e279b6c1SSam Ravnborgsource "drivers/firmware/Kconfig" 2906e279b6c1SSam Ravnborg 2907edf88417SAvi Kivitysource "arch/x86/kvm/Kconfig" 29085e8ebd84SJason A. Donenfeld 29095e8ebd84SJason A. Donenfeldsource "arch/x86/Kconfig.assembler" 2910